. Everyone knows that _______ is dangerous to play with fire, but _______ is difficult is to prevent children from playing with fire.
| A．it, it | B．what, what |
| C．it, what | D．what, it |
I think this software is of little use to your work. It is really a ________ of money.
| A．lack | B．load | C．question | D．waste |
It’s said that this kind of plant only gives off this strange perfume on ________ conditions which the scientists are trying to figure out now.
| A．outstanding | B．certain | C．obvious | D．ordinary |
As we know, success often comes after ______ failure; so don’t be so upset about _______ failure of this matter.
| A．a; a | B．不填; the |
C．a; the | D．不填; a |
It’s crazy of you to spend more time playing computer games than you _______ studying.
| A．are | B．have | C．do | D．will |
--Do you think you can finish the project by five o’clock this afternoon?
---_______. I’ll be busy with my term paper all day.
| A．Not a little | B．Not a chance |
| C．Not a bit | D．Not to mention it |