I ride _________ bicycle to school.[ ]
A. we
B. I
C. my
答案：C
You should make a careful plan ___ the experiment.
A．before to do
B．before doing
C．after to do
D．after doing
非水酸量法所用指示剂有
A．喹哪啶红
B．偶氮紫
C．结晶紫
D．溴麝香草酚蓝
E．α萘酚苯甲醇
