二、根据句意，用括号中所给单词的正确形式填空
1. I think
(cycle) is interesting and I really want to learn how to do it.
2. —What outdoor sport do you recommend?
—Why not try
(jog)? It doesn’t need too much money.
3. She usually
(spend) one hour walking in the park.
4. This is one of the most
(excite) developments in biology in recent years.
5. What other outdoor
(activity) do you know about, boys and girls?
答案：1. cycling 2. jogging 3. spends 4. exciting 5. activities
解析：
1. 此处需用动名词作从句主语，cycle的动名词形式为cycling；2. 固定搭配try doing sth.表示“尝试做某事”，故jog变为jogging；3. 由usually可知时态为一般现在时，主语She是第三人称单数，谓语动词用第三人称单数形式spends；4. 修饰表事物的名词developments，需用-ing形式的形容词exciting，表示“令人兴奋的”；5. other后接可数名词复数，activity的复数形式是activities。
