选词填空。

A. what time  B. What day  C. How many  D. When  E. what

1. —__________ books do you have?

    —I have one.

2. — ________ is it?

    —It's Monday, July first.

3. —______ is National Day?

    —October first.

4. —______ is it?

    —It's six o'clock.

5. —______is this?

    —It's the sun.

在△ABC中，a²+b²+ab<c²，则△ABC是[ ]

A.钝角三角形；

B.锐角三角形；

C.直角三角形；

D.形状无法确定已知方程；