He made a promise __________he would help me.

—What do you think of it?—Well，it’s worth doing ________ the result is satisfactory.

I’m fine — I just felt a bit sleepy and tired, that was ________ I went to bed so early."

The reason ____ he was late for school was _____he had to send his mother to a hospital.

You have to wear a helmet and a life jacket for protection, just ____ you fall into the water.