Section D
1. I am a 15-year-old boy. 我是一个15岁大的男孩。
用连接号“—”构成的词常做一个形容词，放在名词前作定语，此结构中数词后的词不用复数，不能说成 15-years-old, 但不是一个词时，year 要用复数。如：He is 15 years old.
2. ①instead of 代替...,是一个副词短语，不能放主语后独立作谓语动词，只能放在动词后作谓语，它后可接名词/代词/动名词(v-ing)。如：You should play out instead of working indoors.
a) instead 代替… 放句尾或句首。
I don’t like swimming, let’s go hiking instead.
3. I have great fun running.
fun 是不可数名词，意为“乐趣”，词组have fun doing sth. 在做某事中得到乐趣, 如： We have great fun learning English.
注意：have fun= enjoy oneself= ha a good time.
4．Before 和 after 既可作介词，后接动词ing形式。也可作连词，后接时间状语从句。如：
开始跳高前，我们必须弄清楚如何跳得高。
① Before starting jumping, we must get to know how to jump high. （介词）
② Before we start jumping, we must get to know how to jump high. (连词)
5. 短语：
①shout at sb 朝某人吼（不礼貌地）；shout to sb. 朝某人大声地喊
②be import to sb./ sth. 对某人是重要的。如：English is important to us.
③build sb/oneself up增强某人体质 如：Running can build ourselves up.
④立刻，马上：in a minute= right now= right away= at once =soon
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