I was really too busy with my homework and I couldn’t help ____ the housework.

The doctor told me that you just had a strange cold , so you can______.

 Though I haven’t seen Maria for ages, I could ____ her in the crowd at the station.

You’d better not _______ these two sentences, otherwise thereaders cannot fully understand you.

“Stop thief! Stop thief!” But the thief was ________ by the crowd and we lost sight of it.