Tìm lỗi sai và sửa lại cho đúng

Mark the letter A, B, C or D to indicate the underlined part that needs correction in each of the following question
0. His doctor advised him to stop to moke.
     A                  B                 C          D
1. At first life was difficult for me because of I didn't understand English.
       A                       B                      C                            D
2. Copper comes from seven types of ores that also contain the other materials.
                                                  A           B                 C                D
3. Silicon chips contain thousands of circuits in an area as smaller than a fingernail.
                                          A                      B                       C                         D
4.Although Connecticut occupies a small area, its weather can vary from one area to others.
                                            A                                   B                    C                                D