【1】--I'm going to play football this Saturday. What's your p_______?
--I'm going to have a piano lesson.
【2】The invention of Concorde was a huge s_____forward in airplane history.
【3】Don't walk a________the street until the traffic stops.
【4】The plane willt________off in ten minutes.
【答案】【1】plan
【2】step
【3】across
【4】take
【解析】【1】句意：这个星期六我要去踢足球。你的计划是什么？——我要去上钢琴课。形容词性物主代词后跟名词，结合句意可知，答案为plan。
【2】句意：协和式飞机的发明在飞机发展历史上是一个巨大的进步。step forward向前走，站出来，迈步。step此处是名词，受huge的修饰。结合句意可知，答案为step。
【3】句意：在车辆停下之前不要穿过马路。across穿过，指从……表面穿过，结合句意和语境判断，答案为across。