某小组进行“培养液中酵母菌种群数量的动态变化”的实验,在下列实验材料用具中,属于本实验需要的是[ ]
A.琼脂块
B.双缩脲试剂
C.放大镜
D.显微镜
答案:D
艾叶含挥发油()。
A.0.45%~1.00%
B.1.0%~2.5%
C.1%~2%
D.1%以上
E.80%左右
Jack is good ______ all subjects. I look on him ______ my model. [ ]
A. on; for
B. at; to
C. at; as
D. for; as