―Hey, you haven’t been acting like yourself. Everything is OK?
―_________.
| A．Sure, it is | B．I’m fine, thanks |
| C．That’s good | D．It’s a pleasure |
Walking does need a bit of practice _____ gravity has changed.
| A．as if | B．in their turn | C．now that | D．as a result of |
They multiplied and filled the oceans and seas with oxygen, _____ encouraged the later development of early shellfish and all sorts of fish.
| A．that | B．where | C．when | D．which |
_____ is even more important is that as the earth cooled down, water began to appear on its surface.
| A．As | B．That | C．What | D．Where |
It was not immediately obvious _____ water was to be fundamental to the development of life.
| A．what | B．that | C．when | D．why |
-- I wonder if I could possibly use your car for tonight?
---______. I'm not using it anyhow.
| A．Sure, go head | B．I don't know | C．Yes, indeed | D．I don't care |