—What's wrong with you,Eric? You look tired.
—I to prepare for the final exam last night.
A:picked up
B:woke up
C:put up
D:stayed up
我国的河流以外河流为主,唯一注入北冰洋的河流是( )
下边划线的字的字形、注音全对的一组是( )
某同学设计了四份晚餐食谱,你认为比较合理的是( )
某种氟原子的原子核内有9个质子和10个中子,该原子的核电荷数为( )