_____, the students insist that he _____ separated from his desk mate, who is very naughty.
| A．Avoiding to be affected; be |
| B．To avoid to be affected; would be |
| C．Avoid being affected; should be |
| D．To avoid being affected; be |
.In this experiment, they are woken up several times during the night, and asked to report what they＿＿＿＿.
| A．had just been dreaming | B．are just dreaming |
| C．have just been dreaming | D．had just dreamt |
When he was alive, the old scientist used to say that knowledge ＿＿＿＿from practice and he gained his experience by doing a lot of practical work.
| A．was coming | B．had come | C．comes | D．would come |
He ＿＿＿articles for our wall-newspaper these three years, and he ＿＿＿about forty articles.
| A．has been writing； has written | B．has been writing； wrote |
| C．is writing； has been writing | D．has written； has written |
The children ＿＿＿＿＿＿ very quiet； I wonder what they ＿＿＿＿up to.
| A．were； are being | B．are being； are | C．are； do | D．are being； do |
Jim talked for about half an hour yesterday.Never＿＿＿＿＿ him talk so much.
| A．I heard | B．did I hear | C．I had heard | D．had I heard |