定位基准
参考答案:
在加工中确定工件在机床上或机床夹具中占有正确的基准。
实验室配制480ml 0.1mol•L-1的Na2CO3溶液,回答下列问题:
(1)应用托盘天平称取十水碳酸钠晶体______g.
(2)配制时已选用托盘天平、药匙、烧杯、玻璃棒、胶头滴管,还需要用到的玻璃仪器有______.
(3)容量瓶上标有:①温度、②浓度、③容量、④压强、⑤刻度线、⑥酸式或碱式这六项中的______.(填数字符号)
(4)若实验时遇到下列情况,将使溶液的浓度偏低的是______.
A.忘记将洗涤液转入容量瓶;
B.容量瓶洗涤后底部内壁有水珠而未作干燥处理;
C.定容、摇匀、静置后发现凹液面低于刻度线又加水至刻度线;
D.定容时俯视刻度线.
I don't believe in him. You know, what he said doesn't _____ what he did.[ ]
A. agree with
B. agree to
C. agree on
D. agree upon