7个月年龄的婴儿,胸外心脏按压的合适频率为()
A.60~70次/分
B.70~80次/分
C.90~110次/分
D.110~120次/分
E.120~130次/分
参考答案:C
A library with five thousand books___to the nation as a gift. [ ]
A. is offered
B. has offered
C. are offered
D. have offered