单选题 Many firms are （ ）on increasing their markets overseas.

单选题 Frankly speaking, he and I are not real friends, only nodding（ ）.

单选题 It pays to（ ）as much as you can from reading and listening.

单选题 Can you（ ）to memory all the main points of the lecture?

单选题 Neighbors （ ） to the police about the noise from the building site.

单选题 The two friends haven't（ ）with each other for years.

单选题 It is said that the female reporter was（ ）to cover the war in Iraq.

单选题 The naughty boy has no（ ）over himself.