下列各句，标点使用合乎规范的一项是（    ）

L病毒可侵染小鼠的脑膜细胞，引起脑膜炎，L蛋白是L病毒的抗原蛋白．科研人员分别给野生型小鼠转入不同基因，建立了两种模型小鼠．小鼠M在胰岛B细胞表面特异性表达L蛋白，小鼠N在T淋巴细胞表面特异性表达L蛋白受体．将小鼠M和小鼠N杂交，杂交后代中仅在胰岛B细胞表面表达L蛋白、仅在T淋巴细胞表面表达L蛋白受体、两种细胞表面皆不表达、既在胰岛B细胞表面表达L蛋白也在T淋巴细胞表面表达L蛋白受体的小鼠（记为小鼠X）各占 $\frac{1}{4}$ ，据此判断不合理的是（    ）

为抑制商品房价格过快上涨,促进房地产市场健康发展,我国政府采取了一系列增加保障性住房供给的措施,如增加价格明显低于商品房的经济适用房,供低收入者租用的廉租房等。政府出台这些措施是因为(　　)

①增加经济适用房可以减少商品房购买需求

②增加廉租房就能抑制商品房有效需求

③经济适用房与廉租房互为替代品

④增加保障性住房能缓解房地产市场的过度炒作

春秋五霸中最先称霸的是（   ）

阅读下面材料，在空白处填入适当的内容(1个单词)或括号内单词的正确形式。

Lori：Good morning, Chuck. Are you here____(wait) for Professor Johnson?

Chuck：Oh, yes. Good morning, Lori. The professor asked me to come here ____(have) an interview. Do you know something about the job as ____ teacher's assistant?

Lori：Oh, yes. I know all about it ____ Ihave work experience in this field. Last year, I did it for a long time.

Chuck：Really? How did you like ____？

Lori：Well, actually I think it was____(good) I had ever had at school. I was paid nine dollars an hour, which____(be) three dollars more than the school post office paid us.

Chuck：Yeah, I bet this is a good salary. But what did you do?

Lori：My responsibility was to help Professor Johnson grade the students' homework. It wasn't hard and the professor was always available ____ there were any questions. I ____ improve myself through doing this job.

Chuck：I think I would enjoy this kind of work. But I'm a little worried about how much ____ it might take.

Lori：Only about five or six hours a weekand you can do that in your room.

Chuck：It sounds good.