铸件的热处理中：低温退火目的为（），高温退火目的为（）。
参考答案：消除铸造应力；降低铸件硬度
Bob is a police officer. is tall and handsome.[ ]
A. His
B. She
C. He
—Forests are very important to us,aren't they?
—Yes, they can prevent ________ from washing the earth away.[ ]
A. water
B. trees
C. grass
