A successful scientist needs _____ if he wants to make hypothesis (假设) of how processes work and how events take place.
| A．permission | B．penetration | C．imagination | D．convention |
Some insects ______ the colour of their surroundings to protect themselves.
| A．take in | B．take off | C．take on | D．take up |
Mothers holding jobs outside the home should have _______ schedules to make it easier to care for their children.
| A．heavy | B．smooth | C．flexible | D．complex |
We lost our way in that small village, otherwise we ________more places of interest yesterday.
| A．visited | B．had visited |
| C．would visit | D．would have visited |
Had it been possible I would have gone to the movies, but I ________________ busy.
| A．had been | B．am | C．was | D．would be |
In some developed countries, larger population is ______________ in their big cities.
| A．approved | B．gathered | C．concentrated | D．fixed |