— Who found my pen?
— Li Lei _____. [ ]
A. do
B. does
C. did
D. was
C
I still remember the days_______ we lived together.
A．in which
B．which
C．in that
D．that
下列何种情况下，宜选用恒向线航线（）。
A．航程较短或航向接近南北向时
B．高纬度，航向接近东西向时
C．高纬度，航向接近南北向时
D．A＋C
