单选题：As the busiest woman in Norton, she made ____ herduty to loo..

Everyone knows _____ is dangerous to play with fire, but _____ is difficult is to prevent children from playing with fire. [ ]A. that; it B. it; it C. that; what D. it; what

— How I wish I had watched the football match last night.— ________, today's examination would be a total disaster. [ ]A. When necessaryB. If soC. If possibleD. So what

_____ as much as one-fifth of the trees have been cut down.[ ]A. saidB. It saidC. It is said that D. As is said

The boy wanted to ride his father's new motorcycle in the crowed street but his father told him .[ ] A. not to do B. not toC. not do it D. do not so

The archaeologists all find ________ to prepare for the worst conditions they might meet during therestoration.[ ]A. worthyB. it worthwhileC. it worthD. it worthy