对于期货交易,下列说法错误的是()。
A.期货合约由交易所制定
B.实物交割率低
C.期货交易实行实际金额制度
D.期货交易的履约担保由交易所提供
参考答案:C
---John is said to have learned Italian in Italy for five years.
---_______ he speaks it like a native speaker.
A.No doubt
B.No problem
C.No wonder
D.No curiosity
电容器串联使用时,其等效电容量C的()等于各串联电容器电容量的倒数之和。