. It is clear that the whole world is passing through a social revolution in which a central _____ must be taken by scientists and technologists.
| A．process | B．attention | C．measure | D．part |
— Did you meet with the famous space hero?
— ___________ I had come here earlier.
| A．If only | B．If not | C．But for | D．For fear |
The committee ______ five famous scientists put forward a valuable plan at the end of conference.
| A．was made up | B．was made from | C．made from | D．made up of |
They suggested that the library ________ open during the vacation.
| A．was kept | B．would be kept | C．is kept | D．be kept |
If I can help________, I don’t like to working late into the night.
| A．so | B．that | C．it | D．them |
Only by _______ your attention _______ what you are learning can you learn it well.
| A．concentrate; on | B．pay; on | C．concentrating; on | D．paying; on |