红细胞表面积与体积的比值下降可引起红细胞（ ）
A．变形性增大
B．渗透脆性增大
C．悬浮稳定性增大
D．血沉降率降低
E．血红蛋白含量增大
参考答案：B
用括号内所给单词的正确形式填空。
1. I _________ (agree) with you. I don't think you are right.
2. Shanghai is in the __________ (east) part of China.
3. We must have a good __________ (态度) towards study.
4. Would you like some tea or coffee? I _________ (更喜欢) some tea.
5. We must think about the advantages and __________ (advantage) of going by train.
6. Although many Americans move a lot, they still __________ (辨认出) and understand each
other's dialects.
DNA分子中腺嘌呤的含量是15%，则胞嘧啶的含量为（）
A.7.5%
B.15%
C.30%
D.35%
