水泵运行过程中，会造成叶轮前后盘上的压力不平衡，前盘上的压力（）后盘上的压力。
A.大于
B.小于
C.等于
参考答案：B
彼特拉克的《歌集》，主要以（）形式著称。
For derivative contracts, the notional principal is best described as()
A. the amount of the underlying asset covered by the contract.
B. a measure of the actual payments made and received in the contract.
C. being, conceptually and in aggregate, the best available measure of the size of the market.
