清华大学的主楼前是一条路正对着，而非两条路左右分开。
参考答案：对
— How long _____ you _____ in the country with your grandparents, Henry?
— About four weeks. I'll return as soon as school starts.[ ]
A. are; staying
B. did; stay
C. do; stay
D. had; stayed
下图中所标注的主要航路中，证明了地圆学说正确性的是
A．①
B．②
C．③
D．④
