下列说法正确的是( )
A.平面上三点确定一个圆
B.以两条已知线段为弦能画且只能画一个圆
C.以一条已知线段为弦能画且只能画两个圆
D.以一条已知线段为直径能画且只能画一个圆
答案:D
— Will you please help me _____ the exercise books to the students?
— Sorry I have been in a race and my strength has completely _____.[ ]
A. give out; given out
B. give off; given up
C. give out; given in
D. give up; given up
在冲孔时,我们设计锻件图时要设计冲孔连皮,有关说法正确的是()。
A.厚度应适当太厚易锻不足
B.越厚越好
C.孔不管多大都要设计冲孔连皮
D.不需设计浪费时间