【单选题】According to the professor, why is chemistry sometimes called the central science?
A.
Chemistry courses are the most difficult.
B.
Chemical processes occur all around us.
C.
Chemistry students have high status.
D.
Chemists study how to control diseases.
【单选题】The meeting held in our classroom yesterday _____ two hours. [ ]
【单选题】Yesterday we had a long meeting which four hours.
【单选题】The meeting lasted half an hour.
【单选题】呼吸机调节湿化器中高温报警设置不能高于:
【判断题】从运动和构造的角度来看,机器和机构是不一样的。