Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for people to communicate larger amounts of information between two places. The telegram and telephone set the stage for more modern means of communication. With the invention of the cellular phone, communication itself has become mobile. For you, a cell ...
CenaZero♡ | Chat Online | |
06/09 13:05:17 (Tiếng Anh - Lớp 12) |
Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for people to communicate larger amounts of information between two places. The telegram and telephone set the stage for more modern means of communication. With the invention of the cellular phone, communication itself has become mobile.
For you, a cell phone is probably just a device that you and your friends use to keep in touch with family and friends, take pictures, play games, or send text message. The definition of a cell phone is more specific: it is a hand- held wireless communication device that sends and receives signals by way of small special areas called cells.
Walkie - talkies, telephones and cell phones are duplex communication devices: They make it possible for two people to talk to each other. Cell phones and walkie- talkies are different from regular phones because they can be used in many different locations. A walkie- talkie is sometimes called a half- duplex communication device because only one person can talk at a time. A cell phone is a full- duplex device because it uses both frequencies at the same time. A walkie-talkie has only one channel. A cell phone has more than a thousand channels. A walkie- talkie can transmit and receive signals across a distance of about a mile. A cell phone can transmit and receive signals over hundreds of miles. In 1973, an electronic company called Motorola hired Martin Cooper to work on wireless communication. Motorola and Bell Laboratories (now AT& T) were in a race to invent the first portable communication device. Martin Cooper won the race and became the inventor of the cell phone. On April 3, 1973, Cooper made the first cell phone call to his opponent at AT& T while walking down the streets of New York city. People on the sidewalks gazed at cooper in amazement. Cooper's phone was called A Motorola Dyna- Tac. It weighed a whopping 2.5 pounds (as compared to today's cell phones that weigh as little as 3 or 4 ounces)
After the invention of his cell phone, Cooper began thinking of ways to make the cell phone available to the general public. After a decade, Motorola introduced the first cell phone for commercial use. The early cell phone and its service were both expensive. The cell phone itself cost about $ 3, 500. In 1977, AT & T constructed a cell phone system and tried it out in Chicago with over 2, 000 customers. In 1981, a second cellular phone system was started in the Washington,D.C and Baltimore area. It took nearly 37 years for cell phones to become available for general public use. Today, there are more than sixty million cell phone customers with cell phones producing over thirty billion dollars per years.
What is the main idea of the passage? Lựa chọn một trả lời để xem Đáp án chính xác Báo sai đáp án hoặc câu hỏi |
A. The increasing number of people using cell phone. 0 % | 0 phiếu |
B. The difference between cell phones and telephones. 0 % | 0 phiếu |
C. The history of a cell phone 0 % | 0 phiếu |
D. How Cooper competed with AT& T. 0 % | 0 phiếu |
Tổng cộng: | 0 trả lời |
Trắc nghiệm liên quan
- Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for ... (Tiếng Anh - Lớp 12)
- Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for ... (Tiếng Anh - Lớp 12)
- Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for ... (Tiếng Anh - Lớp 12)
- Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for ... (Tiếng Anh - Lớp 12)
- Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for ... (Tiếng Anh - Lớp 12)
- Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for ... (Tiếng Anh - Lớp 12)
- For a time, the Hubble telescope was the brunt of jokes and subject to the wrath of those who believed the U.S government had spent too much money on space projects that served no valid purpose. The Hubble was sent into orbit with a satellite by the ... (Tiếng Anh - Lớp 12)
- For a time, the Hubble telescope was the brunt of jokes and subject to the wrath of those who believed the U.S government had spent too much money on space projects that served no valid purpose. The Hubble was sent into orbit with a satellite by the ... (Tiếng Anh - Lớp 12)
- For a time, the Hubble telescope was the brunt of jokes and subject to the wrath of those who believed the U.S government had spent too much money on space projects that served no valid purpose. The Hubble was sent into orbit with a satellite by the ... (Tiếng Anh - Lớp 12)
- For a time, the Hubble telescope was the brunt of jokes and subject to the wrath of those who believed the U.S government had spent too much money on space projects that served no valid purpose. The Hubble was sent into orbit with a satellite by the ... (Tiếng Anh - Lớp 12)
Trắc nghiệm mới nhất
- Đọc đoạn văn sau: VIẾNG LÊ-NIN Mát-xcơ-va, tháng 1 năm 1924, giữa mùa đông nước Nga. Khí trời lạnh dưới 40 độ âm. Lê-nin vừa mất được mấy hôm. Một sáng, phòng số 8 khách sạn Luých có tiếng gõ cửa nhẹ. Một thanh niên gầy gò, đầu đội mũ cát-két, mình ... (Tiếng Việt - Lớp 4)
- Đọc đoạn văn sau: CÂY XƯƠNG RỒNG Ngày xưa, người ta sinh ra, lớn lên và cứ thế trẻ mãi. Khi đã sống trọn vẹn cả một cuộc đời thì lặng lẽ chết đi. Tất cả các cô gái đều biến thành loài hoa còn tất cả những chàng trai đều biến thành đại thụ. Vào lúc ... (Tiếng Việt - Lớp 4)
- Đọc đoạn văn sau: LỖI LẦM VÀ SỰ BIẾT ƠN Hai người bạn cùng đi qua sa mạc. Trong chuyến đi, hai người nói chuyện với nhau và đã có một cuộc tranh cãi gay gắt. Một người nổi nóng, không kiềm chế được mình đã nặng lời miệt thị người kia. Người kia cảm ... (Tiếng Việt - Lớp 4)
- Đọc đoạn văn sau: QUẢ CẦU TUYẾT Tuyết rơi ngày càng dày. Một đám học sinh vừa ra khỏi cổng trường, chúng nắm những quả cầu bằng thứ tuyết ẩm, cứng và nặng như đá, ném vào nhau. Vỉa hè rất đông người qua lại. Bỗng người ta nghe một tiếng hét to bên ... (Tiếng Việt - Lớp 4)
- Đọc đoạn văn sau: PHÉP MÀU GIÁ BAO NHIÊU? Một cô bé tám tuổi có em trai An-đờ-riu đang bị bệnh rất nặng mà gia đình không có tiền chạy chữa. Cô nghe bố nói với mẹ bằng giọng thì thầm tuyệt vọng: “Chỉ có phép màu mới cứu sống được An-đờ-riu”. Thế là ... (Tiếng Việt - Lớp 4)
- Một chiếc đồng hồ cổ có kim phút dài gấp 3 lần kim giờ. Khi kim phút quay được 30 vòng thì kim giờ quay được số vòng là: (Toán học - Lớp 5)
- Có ba thùng đựng kẹo. Trung bình cộng số ki-lô-gam kẹo trong thùng thứ nhất và thùng thứ hai là 150,5 kg. Biết thùng thứ nhất ít hơn thùng thứ hai 20,3 kg và gấp 2,5 lần số ki-lô-gam kẹo ở thùng thứ ba. Hỏi thùng thứ ba có số ki-lô-gam kẹo là: (Toán học - Lớp 5)
- Dưới đây là bảng số liệu về kết quả quay một bánh xe số 30 lần: (0,5 điểm) Mặt số 1 2 3 4 5 6 Số lần 5 7 3 6 4 5 Hãy cho biết tỉ số số lần xảy ra sự kiện 2 chấm xuất hiện và tổng số lần quay. (Toán học - Lớp 5)
- Chiều cao thực tế của một tòa nhà là 20 m, biết bản đồ có tỉ lệ 1 : 400. Vậy chiều cao tương ứng trên bản đồ là: (Toán học - Lớp 5)
- Số thập phân có giá trị bằng 45,67 là: (Toán học - Lớp 5)