periment shows that proper amounts of exercise, if regularly, can improve our health.

Last Monday, I bought a second-hand computer, ______ was very slow.

We should take good care of the elderly, as they are ______ to the sudden change of weather.

下列对《氓》选段的理解和分析，不正确的一项是（ ）桑之未落，其叶沃若。于嗟鸠兮，无食桑葚。于嗟女兮，无与士耽。士之耽兮，犹可说也。女之耽兮，不可说也。桑之落矣，其黄而陨。自我徂尔，三岁食贫。淇水汤汤，渐车帷裳。女也不爽，士贰其行。士也罔极，二三其德。

Put the top back on that felt－tip pen or it will __________.-OK.I will.