. It used to be thought _____ the Earth was flat.
| A．as | B．when |
| C．since | D．that |
We made plans for a visit but _____ difficulties with the car prevented it.
| A．consequent | B．subordinate |
| C．substantial | D．subsequent |
He didn't _____ what I read because his mind was on something else.
| A．hold on | B．catch on | C．take in | D．get over |
Scientists have to work hard to keep _____ with modern discoveries and developments.
| A．company | B．track | C．touch | D．pace |
She _____ the temptation to buy a coat she could not afford.
| A．challenged | B．obstructed | C．contradicted | D．resisted |
He put in a special _____ for an extra day's holiday so that he could attend his daughter's wedding.
| A．request | B．demand | C．inquiry | D．proposal |