—______ big river it is !
—Yes. I am afraid I can't swim ______ it .
A:What a, across
B:How, past
C:How a, over
D:What, through
支____ 兆____
专____ 韦____
更____ 由____
皮____ 立____
雅丹地貌是由于流水作用形成的。