词汇网络: been

am

First person singular present tense of 'be'.

A1

is

Third person singular present of 'be'. To exist or describe a state.

A1

was

First and third person singular past of 'be'.

A1

were

Second person singular past and all plural past of 'be'.

A1

are

Second person singular and plural present form of 'be'.

A2

be

To exist; to happen; to continue in a particular state.

A2