Question

The birds leave the town if we don’t build up nesting boxes. (HAVE TO) Ken clean out the pond. (NOT HAVE TO) We collect the rubbish during the rain yesterday. (HAVE TO)

Answer 1

The birds will have to leave the town if we don’t build up nesting boxes

ken doesn’t have to clean out the pond

we had to collect the rubbish during the rain yesterday

Answer 2

The birds have to leave the town if we don't build up nesting boxes. Ken doesn't have to clean out the pond. We had to collect the rubbish during the rain yesterday.