We set off _______ the Three Gorges _______ a beautiful afternoon from Fu Ling.

We set off _______ the Three Gorges _______ a beautiful afternoon from Fu Ling.

A．to; at             B．from; on          C．through; on        D．for; on

 He set off down the main street. He _____.

He set off       his missing dog.

A. in search for     B. search for         C. search of          D. in search of

We set off early ____ next morning and came to ____ unknown valley after about an hour.