能被石油醚溶解的是（） A.糖类 B.三萜类化合物 C.苷类 D.香_爱下问搜题

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问题单项选择题 B型题

能被石油醚溶解的是（）

A.糖类

B.三萜类化合物

C.苷类

D.香豆素

E.游离生物碱

答案

参考答案：B

解析：糖类为极性化合物，易溶于极性较大的水中；三萜类化合物为非极性化合物，最易溶解于石油醚。

阅读理解

根据表格内容，从A、B、C三个选项中选出能回答所提问题的最佳答案。

Items	Group One	Group Two	Group Three	Group Four
1. Answer correctly	67	71	76	78
2. Answer quickly	76	80	79	62
3. Answer humorously	69	68	81	77
4. Speak freely	81	83	94	85
5. Speak clearly	88	86	93	86
6. Speak loudly	90	93	91	91
7. Have good manners	79	74	75	79
8. Co-operate well	82	63	88	84
9. Average	79	77	82	80

1. ________ is the most humorous of all the four groups.

A. Group One
B. Group Two
C. Group Three

2. Group Two is thought to have spoken as ________ as Group Four.

A. clearly
B. quickly
C. freely

3. Group Two did worst in "________."

A. Answer correctly
B. Speak freely
C. Co-operate well

4. In "Answer correctly", Group Three got ________ more marks than Group one.

5. According to the table, which of the following is NOT true?

A. Group Three is the winter of the competition.
B. Group One did as well as Group Four in "Answer correctly" of all the items.
C. All groups did best in "Speak loudly" of all the items.

问答题

细胞生物学的主要研究内容有哪些？