不设专门的对照的研究是
A.病例对照研究B.队列研究C.个案调查D.分析性研究E.实验研究
参考答案:C
-Could you please come to help me _ dinner?
-I’d like to. But I have to finish my work _ . [ ]
A. make ; at first
B. cook ; at first
C. make ; first
D. have ; first
机动车仪表板上(如图所示)亮表示发动机可能机油量不足。