—— Look at the black clouds.It ＿＿＿＿＿＿ soon.
—— Sure.If only we ＿＿＿＿＿out.
| A．is raining； didn’ t come | B．is to rain； won’ t start |
| C．will rain； haven’ t started | D．is going to rain； hadn’ t come |
The research is so designed that once________nothing can be done to change it.
| A．begins |
| B．having begun |
| C．beginning |
| D．begun |
Visitors________not to touch the exhibits.
| A．will request |
| B．request |
| C．are requesting |
| D．are requested |
It is known to all that________you exercise regularly, you won't keep good health.
| A．unless |
| B．whenever |
| C．although |
| D．if |
—What would you do if it________tomorrow?
—We have to carry it on, since we've got everything ready.
| A．rain |
| B．rains |
| C．will rain |
| D．is raining |
We all know how difficult it is for all of us to eat better, exercise more, and sleep enough________we know we should.
| A．because |
| B．even though |
| C．as if |
| D．when |