choose past simple or past continuous:

Be careful. The train comes/ is coming.

I often am flying/ fly by plane.

sport helps/is helping us to be healthy.

I write/am writing my letter now.

is coming

fly

helps

am writing

1) Be careful. The train is coming. 2) I often fly by plane. 3) Sport is helping us to be healthy. 4) I am writing my letter now.