Front

Helping verb in 'They are thinking about traveling.'

Back

are

Front

Helping verb in 'She is playing football.'

Back

is

Front

Helping verb in: 'She will read a book.'

Back

will

Front

Helping verb in 'We have done our homework.'

Back

have

Front

Main verb in: 'My little sister is growing fast.'

Back

growing

Front

Main verb in: 'He is working at the mall.'

Back

working