当机组使用氧气面罩时

I was busy yesterday, otherwise I     （）     your birthday party.

Supposing I    （）  this gift, what would he say?

It is important that I （）    with Mr. Willians immediately.

He insisted that John （）     it.

He spoke in a quiet, distinct voice, as though his thought        （）

If it     （）     tomorrow, what would we do?

If it    （）      rain, we （）        get wet.

It is required that you    （）        at six.

If he had not gone out in the storm （）          .

The boy acted     （）       he had never lived in Canada before.