问题 选择题

在炎热的夏天,皮肤的反应是(  )

A.多数血管舒张,血流量大,皮肤温度高

B.多数血管收缩,血流量小,皮肤温度低

C.多数血管收缩,血流量大,皮肤温度高

D.多数血管舒张,血流量小,皮肤温度低

答案

皮肤由表皮和真皮组成,真皮里含有丰富的毛细血管.在炎热的夏天,外界气温较高,皮肤内的大多数血管扩张,血流量增多,皮肤的温度会升高,因而由皮肤直接散发的热量增多,与此同时,汗液分泌增多,通过汗液的蒸发,又从体表带走一部分热量,这样可以使人的体温保持正常,而不致升高;外界气温较低时,皮肤内的大多数血管收缩,血流量减少,皮肤温度降低,又皮肤直接散发的热量减少,与此同时,汗液分泌减少,通过汗液蒸发散失的热量也减少,这样可以使人的体温保持正常,而不致降低.如图:

故选:A

听力题

根据横线上的首字母提示或括号内的汉语提示完成句子。每空一词,请将答案写在答题卡上的规定位置。

小题1:In communication, a smile is usually a strong sign of a friendly and open a______________.

小题2:Do you have enough to c________ all your daily expenses?

小题3:We were a________________ to hear that she passed the test without much difficulty.

小题4:ThesceneryinSwitzerland, which is beyond d____________(描述), is attractive to the tourists from the whole world.

小题5:This July, a group of teaching ___________(志愿者) from Tsinghua University visited the school and launched the public service program entitled “The One Class” there.

小题6:Read the _________________(说明) carefully before you take the pills.

小题7:Peking duck is usually s__________ with steamed pancakes, which is used to wrap the meat and

slices of cucumber and shallots;

小题8:The number of foreign students studying in China has been ___________(增长) year by year.

小题9:Pandas are e____________ animals. There aren’t many of them left.

小题10:Manatees’ favorite ________________(栖息地) is the water under the trees in mangrove swamps.

小题11:Did you know that tea was invented by a________________?

小题12:Your views on education are _________ (相似的)to mine.

小题13:In Paris, it’s usually c_______________ to take the underground train to most places.

小题14:Take a deep breath and hold it in your chest. It can ___________(有效) control your anxiety.

小题15:If you pay some attention, you could easily point out some improper b_________ happening around: young men refusing to give seats to the old on buses; shoppers jamming into queue instead of waiting in line; rude riders neglecting red lights, etc.

单项选择题