1) He would never do anything to ________ the lives of his children.
A. danger B. dangerous C. endanger D. endangered
2)Laws have been introduced to prohibit ______ endangered animals.
A. killing B. to kill C. killed D. kill
3) They collected more garbage in 1998 than they ______ in 1995.
A. did B. had had C. had done D. had
4) Animals _____ in the zoo know nothing about the life in the forest.
A. were born B. to born C. had been born D. born