. It was not until she got home ___ Jennifer realized she had lost her keys.

第二次工业革命把人类带入了一个新的时代。下列最能体现“新的时代”特征的发明是（    ）

下面式子是方程的是（    ）

已知双曲线 $\frac{x^2}{2}-\frac{y^2}{a^2}=1$ 过点（2，﹣1），则该双曲线的渐近线方程为（   ）

选词填空。

excited, skill, may, they, without, but, include, part

    American teenagers(青少年)enjoy doing part-time jobs．They think it's an important____of growing up．They can learn some important____by doing part-time jobs and they can also make some money in this way．
    American teenagers usually begin to do part-time jobs at the age of 14．On weekdays，they____go to work a few hours a week after school．They usually work for longer at weekends．
    In summer,American teenagers are____if they find part—time jobs at camps or swimming pools．These jobs can bring____much fun．
    Some difficult jobs____teaching， nursing and police work．____these jobs can be helpful for their future．When they grow up，the students with work experience are more likely (可能的)to be successful than those____work experience．