一般现在时：The moon moves around the earth.

As soon as i arrive here,i will telephone you.

一般过去时：I saw him in the street yesterday.

When we were girls,we used to dance and sing together.

现在进行时：He is writing a letter to his parents now.

He is always helping others.

过去进行时：While i was watching TV, my husband was reading the newspaper.

My grandfather was always helping others before he died.

一般将来时：Shall we go to the park?

It's going to rain.

过去将来时：Last Sunday we were going to go for a picnic but it rained.

Little did they know they were to reunite ten years later.

现在完成时：We have seen the film before.

It's the most exciting moment i've experienced.

过去完成时：By the time we got there, the play had already begun.

If i had known it i would have told you.

现在完成进行时：I have been waiting for you for one hour.

What have you been doing since i saw you last time?