1.He ____(look) round when he heard the sound behind him.

1.He ____(look) round when he heard the sound behind him.
2.I ____(show) them around our school when they get there.
3.Where ____you____(be)?
To the library.
请用括号内词语正确的形式填空,最好能说明理由.

1.He was looking(look) round when he heard the sound behind him.
2.I will show (show) them around our school when they get there.
3.Where have you been (be)?
To the library.
---绝对正确!