.He spent more than twice as much time on the problem _____ I spent on it .
A dark blue design will not on a blackboard.
The store had to a number of clerks because sales were down.
. It was so noisy out side that he couldn’t down to read.
He offered to her a hand as the suitcase was too heavy for her to carry.
----When did the concert? ---Well, two or three years ago?