题目

地球上最大的生态系统是（ ） A . 森林生态系统 B . 生物圈 C . 海洋生态系统 D . 草原生态系统 答案：B3．Tom went against his promise ______ he would never cheat in exams, ______ made him unpopular with his classmates.A．that; thatB．which; thatC．that; whichD．which; which