人体不补充氧气长时间飞行的最大高度约为()
A.3000米
B.4500米
C.6000米
D.7500米
参考答案:B
---People should use public transport instead of their own private cars.
--- _______.The roads are too crowd as it is.
A.All right.
B.Exactly.
C.Go ahead.
D.Fine.
文艺复兴首先发生在
A.西班牙
B.意大利
C.法国
D.英国