Here are the completed sentences:

1. They have an extremely **user-friendly** website which allows visitors to source by brand.
2. Samsung CEO confident that Galaxy S10 will meet your **expectations**.
3. Teenagers often start smoking because of **peer** pressure.
4. I can’t stand with such a **chatty** person like her. She talks too much every day.
5. That man is a **bully** who intimidates his wife and children into doing what he wants.
6. My new mobile phone can **navigate** the web easily and fast.
7. It really **annoys** me when people forget to say thank you.
8. He’s not **mature** enough to be given too much responsibility.
9. We’re preparing for the midterm tests. It’s really **stressful**.
10. I want to **transfer** data to the computer network storage from my office computer.
11. I couldn’t **concentrate** on my work. My mind was on other things.
12. Please inform me of your arrival time **ASAP**.