. I_______such a foolish mistake if I had been a little more ca
reful.
| A．wouldn’t make | B．hadn’t made |
| C．wouldn’t have made | D．didn’t make |
Most birds find it safe to sleep in the trees, but _______they have eggs or young chicks, they don’t use a nest.
| A．why | B．how | C．unless | D．where |
_______ boys and girls in that school are almost equal.
| A．A number of | B．The numbers of | C．Numbers of | D．The number of |
Every possible means ______to prevent the air pollution, but the sky is still not clear.
| A．is used | B．are used | C．have been used | D．has been used |
It’s already 10 o’clock. I wonder how it_______ that she was two hours late on such a short trip.
| A．came over | B．came about | C．came out | D．came up |
Gone are the days when women were ____
| A．looked down | B．looked up | C．looked around | D．looked down upon |