工程变更的补偿范围，通常以（）一定的百分比表示。
A．合同税率
B．变更税率
C．合同金额
D．变更金额
参考答案：C
They put forward a lot of plans at the meeting, none of _______ were carried out in their work.
A．which
B．them
C．what
D．that
论述空调低压侧压力偏高，高压侧压力偏低故障的原因及检修方法？
