He will come to call on you the moment he ____ his painting.

 ____ difficult the task may be, we will try our best to complete it in time.

It was ____ that she couldn’t finish it by herself.

I’m thirsty. Will you get me something ____?

 How long did you spend ____ your new house yesterday?

It was great fun _____ a picnic on the hill. 

----Lily, keep the window ____. The sandstorm hasn’t stopped yet. ----OK, I’ll do that.

A policeman saw two thieves ____ a girl’s mobile phone on a bus and he caught them at once.

 It’s bad for your eyes ____ computer games for a long time. 

The scientist suggested ____ the experiment in a different way.