为了不产生乱纹，开始滚花时，挤压力要______。
A．大
B．均匀
C．小
参考答案：A
When the earthquake, a destructive natural disaster, happened, ninety-nine coal miners were trapped
in the coal mine _____the ruins, waiting _____.[ ]
A. in; to be rescued
B. under; for being rescued
C. in; to rescue
D. under; to be rescued
已知ab=3，a+b=7．
（1）求a2+ab+b2的值；
（2）求（a-b）2的值．
