(单选题)6: 缺氧对呼吸的刺激主要是通过 A: 直接刺激中枢的呼吸神经元 B: 刺激中枢化学敏感区 C: 刺激颈动脉体和主动脉体感受器 D: 刺激颈动脉窦和主动脉弓感受器 E: 刺激心肺感受器 ...

23：Life is too boring in the countryside. You can hardly find any ____. A：entertainment B：job C：homework D：movie ...

17：Alice is the only one of the students in our school who ____ Australia. A：has gone to B：has been to C：have gone to D：have been to ...

11：I would have come earlier, but I ____ that you were waiting for me. A：didn’t know B：hadn’t know C：would have known D：haven’t known ...

5：Soon the heart monitor showed a (subtle) change-an uneven curve instead of a flat line. A：large B：slight C：exciting D：obvious ...

24：For Micherner,it signaled a new beginning,lauching him in his 40s on a (spectacular) career. A：an impressive B：a successful C：an expressive D：a good ...

18：With the ____of Mary, all the girl students are eager to go to the party. A：exhibition B：exception C：except D：reception ...

12：But for the party, he ____ of hunger fifteen years ago. A：would have died B：would die C：must have died D：must die ...

6：Jane＇s a socialable girl, as soon as she meets strangers, she can quickly get ____ with them. A：known B：acquainted C：polite D：shocked ...

25：He is not ____ a fool ____. A：such…as he is looked B：such…as he looks C：as…as he is looked D：so…as he looks ...