YB45包装机当热电偶在（）秒钟时间内探测出七号轮烙铁温度变化超过20℃则显示“第七轮恒温器故障”故障。
A.一
B.二
C.四
D.三
参考答案：A
I was told that there were about 50 foreign students __________ Chinese in the school, most __________were from Germany.
A．study; of whom
B．study; of them
C．studying; of them
D．studying; of whom
氨碳比
