题目

 ─ Fangfang seems lost in thought over there.  ─ Yes, she is thinking _____ she will work in Beijing or in her hometown after graduation.  A. that                         B. whether                C. which                   D. how   答案：B17．生物圈中的生物世代相续，生生不息，是因为生物通过（　　）实现的．A．生殖B．遗传C．生殖和发育D．发育