【单选题】
I have spent a lot of time（）working on this problem.
A、at
B、–（不填）
C、on
D、with
查看正确答案A、heard B、heard of C、heard from D、heard a lot
搜题
更多“I have spent a lot of time（）working on this problem.”相关的问题
第5题
A、I/O接口即I/O控制器，用来连接I/O设备与主板 B、I/O接口用来连接I/O设备与主机 C、I/O接口用来连接I/O设备与主存 D、I/O接口即I/O总线，用来连接I/O设备与CP
第6题
A、Oh, fantastic! Fresh air, and B、Come on, I've got lots of fun C、By the way, I don't like Saturdays D、Well, I'll look forward to your phone call sunshine every day
