问题补充:
To reach Africa, we flew high mountains, deep valleys and
great deserts(沙漠).
A. on, across, though
B. over, through, through
C. over, through, across
D. on, in, across
答案:
A. on, across, though
B. over, through, through
(答案→)C. over, through, across
D. on, in, across
解析:介词辨析。Over越过(从空中);through穿过(从内部穿过);across从表面越过;on在..上面;in在…里面;句意:为了到达非洲,我们飞越高山,穿过峡谷,跨越沙漠。故C正确。