Swimming is a very good way for us to get physical exercise because ___. ( )

A.it can help us improve our speed.

B.it can help us improve our endurance.

C.it can work on all our major muscle groups.

D.it can reduce pressure on our joints and bones.

正确答案：it can help us improve our speed.

it can help us improve our endurance.

it can work on all our major muscle groups.

it can reduce pressure on our joints and bones.