Look at the picture ______ the right[ ]

When did your computer go wrong? -Last night, while I_______ some music from a website.

The traffic was busy on our way to the train station, _____ we caught the train on time at last.

Look! It ____ hard now. You’d better wait for a while until it stops.

You aren’t supposed to ask the boy to buy things for you. _______, he is too young.