金属指示剂的僵化现象可以通过( )来消除。
A．加入有机溶剂或加热
B．加水
C．放置
D．增加用量
参考答案：A
用am，is，are填空
1. What _____ those? _____ they birds?
2. He _____ my friend. _____ your friend a boy or a girl?
3. This _____ his ruler. Where _____ my ruler?
4. I _____ in Class Three. _____ you in Class Three,too?
5. Those _____ their apples. Where _____ his apples?
