问题
I worked on the problem ____ a long time and I worked it out ____ myself ____ last.[ ]
A: for; by; at
B: in; with; on
C: on; by; in
D:for; for; at the
B: in; with; on
C: on; by; in
D:for; for; at the
正确答案是：
同类题型
Some of my friends are interested in science, but none of them can tell ____________.
Isshoppinghereveryexpensive?—Yes,thepricerun _______fiftydollars.[ ]
Have you ever been to Shanghai?— Yes. I there with my father last year.
My bag is the same _____ Li Fen’s.[ ]
John, you ____ the computer game for two hours. It’s bad for your eyes. Stop, please!—OK, Mum.