28. The book was written _____ careful observations and detailed studies.
| A．on the ground of | B．on behalf of | C．on average | D．on the basis of |
In modern times, the development of science is ________ .
| A．thought well of | B．thought highly |
| C．highly thought of | D．well thinking of |
He insisted that his plan _______ carried out at once.
| A．would be | B．could be | C．was | D．should be |
In order to have a good _______ of English, he decided to go abroad for further education.
| A．command | B．need | C．master | D．direction |
A series of books in the library ____ been stolen so that the number of them ____ smaller than before.
| A．have, is | B．has, is | C．has, are | D．have, are |
It was announced that only when the fire was under control _______ permitted to return to their homes.
| A．would villagers be | B．villagers would be |
| C．should villagers be | D．villagers should be |