It is typical of students to stay up ________ deep into the night for the final exam．
| A．to read | B．having read |
| C．to have read | D．reading |
Radium salts, which have been found to _____ in bones, give rise to cancers of the bone.
| A．pile up | B．build up | C．keep up | D．pull up |
Having said he would mend the clock, he discovered that he had not brought the _____ tools for the job.
| A．concise | B．correct | C．right | D．precise |
The country needs a _____ government. We have had three Prime Ministers in a year.
| A．stationary | B．changeless | C．constant | D．stable |
There is a 20 minute parking _____ here, so we must get back to the car very quickly.
| A．freedom | B．limit | C．allowance | D．prohibition |
Because of the poor harvest, wheat prices have _____ in the last six months.
| A．added | B．jumped | C．amounted | D．developed |