用所给词的适当形式填空。(20分)
now then is was are were
（1）A：________ he strong then?
B：Yes，he________．
（2）A：Where________ he now?
B：He________ at school.
（3）A：________ you at home yesterday?
B：Yes，I________．
（4）A：Shenzhen wasn't big________．
B：It is a big city________．