There has to ______ a well-developed system that can give people a warning when a tsunami is ______ the way.
| A．have；in |
| B．be；in |
| C．have；on |
| D．be；on |
At times the balance in nature is ______ , resulting in a number of possibly unforeseen effects.
| A．troubled | B．confused | C．disturbed | D．puzzled |
He _____the problem _____in his mind for a whole week before he did anything about it.
| A．switched; on | B．kicked; up | C．turned; over | D．took; on |
You _____only half the price ,how would the seller sell the jacket to you ?
| A．spent | B．paid | C．charged | D．offered |
In the cross-lake swimming race, a boat will be ____in case of an emergency.
| A．standing by | B．turning on | C．getting on | D．running on |
The teacher has a peculiar way of ______her student’s nervousness when then speak English.
| A．breaking down | B．going over | C．taking off | D．giving away |