液压捣固机每次夹实时，捣固掌夹到行程终了以后，应在道床内轨枕两侧夹持（）s。
A.1～2
B.2～3
C.3～4
D.4～5
参考答案：B
He was hoping to go abroad but his parents_________ that they won’t support him unless he can borrow money from the bank.
A．were deciding
B．decided
C．have decided
D．will decide
用NaCl固体配制1mol/L的NaCl溶液100mL．
（1）实验室有下列仪器：①玻璃棒；②胶头滴管；③100mL量筒；④100mL容量瓶；⑤250mL量筒；⑥托盘天平；⑦50mL烧杯；应选用的仪器（填编号）______．
（2）应称取NaCl的质量为______．
（3）在定容时，不小心滴加的蒸馏水超过了刻度线，处理的方法是______；将NaCl溶液转移到容量瓶后，未对烧杯和玻璃棒进行洗涤，则所得溶液的浓度（填“偏高”或“偏低”或“不变”）______．
