1. C. by

by → carry (carry: đưa, bưng, mang theo)

(*don't try to copy*)

2. C. will see

will see → see (tôi sẽ đưa nó cho anh ấy khi tôi sẽ thấy anh ấy → tôi sẽ đưa nó cho anh ấy khi tôi thấy anh ấy)

(*I despise people who copies mine without voting me 5 stars or give credit to me...*)

3. B. since (since: từ khi; because: tại vì)

since → because 

(*do not copy or if you copied mine, please consider making some of your answers different from mine*)

4. A. learned

learned → is learning (V_ing)

5. C. eight-hours

eight-hours → eight-hour (nếu dùng "-" thì không cần s hay es)