In some developed countries, larger population is ______________ in their big cities.
| A．approved | B．gathered | C．concentrated | D．fixed |
. We can’t wait. We have to the direction and the distance before we take action.
| A．make out | B．figure out | C．think out | D．turn out |
We want our children to know that hard work .
| A．comes off | B．gives off | C．pays off | D．sees off |
. Teaching a pronunciation class to a mixed group of learners can a teacher with many challenging problems.
| A．provide | B．produce | C．present | D．offer |
If you do not feel well, you should not ____going to see the doctor. ?
| A．pick out | B．give off | C．put off | D．make out |
The period ____dance classes increases gradually from two or three hours a day to five or six.
| A．referred to | B．kept to | C．got to | D．given to |