权利质押中，关于本票、提单、存款单的出质说法正确的是（）。
A.只有存款单可以
B.只有本票、存款单可以
C.都不可以
D.都可以出质
参考答案：D
______ their homework, these three students have to stay in the classroom for another thirty minutes.
A．Not finishing
B．Not finished
C．Having not finished
D．Not having finished
电动机温度升高有哪些原因？
