5. We ______ thousands of trees if we don’t waste paper. A. would save B. will save C. could save D. must save 6. Floods, droughts can easily _______ a harvest. A. kill B. harmful C. destroy D. change 7. What subject is _______ at school? A. difficult B. as difficult C. the most difficult D. the more difficult 8. I never mind _______ up early in the morning. A. getting B. to get C. got D. geting 9. Peter was not feeling well, so we gave him _______ to do than you. A. fewer work B. less work C. little work D. least work 10. Tom closed all the windows _______ the rain could not come in. A. because B. in order to C. as D. so that