【简答题】How much will you pay for your second child if you take two children along?
【单选题】The well-known singer was ______ at the electronic organ by his school teacher.
【判断题】细胞膜两侧某种离子所具有的浓度势能差和电势能差的代数和称为该离子的电--化学势能。
【简答题】计算:(3a 3 b-9a 2 b 2 -21a 2 b 3 )÷3a 2 b.
【单选题】Will you pay cash for the goods, madam, or would you like them______to your account?