6. Doing your homework is a sure way to improve your test scores, and this is especially true _____ it comes to classroom tests.
A. when
B. since
C. before
D. after
7. Don't worry. The company will _____ all your expense.
A. satisfy
B. meet
C. pay
D. submit
8. Eventually, people spread throughout the continent, ______ the entire species.
A. wiping out
B. wiping away
C. wiping off
D. wiping up
9. Experts say walking is one of the best ways for a person to ______ healthy.
A. preserve
B. stay
C. maintain
D. reserve
10. Faced with the ______ difficulties, they are determined to carry on their program.
A. satisfactory
B. attributable
C. innocent
D. intangible
