—Shall we go out for a walk?—Sorry, I can’t. I _______ my homework.
______ girl in red is my best friend, Sally.
---A: Sorry, I didn’t return your book on time.---B: _______.
---A: Sophia, your handwriting is really beautiful. I love it.---B: _______.
---I called you at 4:00 yesterday afternoon, but nobody answered.---Sorry, I ______ with my friends at that time.
The WHO has given some advice on to prevent us being infected(感染)with H7N9.