金属材料切削性的好坏，主要取决于（）。
A、硬度
B、强度
C、塑性
D、韧性
参考答案：A
––Has your brother ever been to the Sand Lake?
––Yes, he has _______ the Sand Lake many times.
A．been to
B．gone to
C．go to
D．went
执行如下程序，最后S的显示值为 SET TALK OFF S=0 i=5 X=11 DO WHILE S＜=x S=S +i I = I +l ENDDO s SET TALK ON
A．5
B．11
C．18
D．26
