We must stop these children (from) playing football in the street . 我们必须阻止孩子们在大街上踢足球。
5. put up a notice saying “Keep off”= put up a notice on which is written “Keep off”立一个上面写有“勿踩踏”的牌子
注意 keep off 在上下文中的不同意思有：避开，挡住，制止吃喝，不吃不喝……
Do be careful to keep off the dangerous dog . 务必躲开那条危险的狗。
After his illness the old man kept off noodles for a week .
The only way to get your weight down is to keep off fat . 减肥的唯一办法是不要吃肥肉。
Wet paint ! Keep off ! 油漆未干，请勿靠近 ！
6. do some studying 学点习
It is useful for you to do some studying in your spare time .
7. masses of 大量的，大批的（修饰可数或者不可数名词）
Can\'t you see I have masses of things to see to today ? 你没看到我今天有很多的事要处理吗 ？
I have masses of unanswered letters this week . 本周我有一大堆来信没有回。
The majority of us are worried about masses of homework on Sunday . 我们大部分都担心星期天的许多作业。
8. watch the news on television 看电视新闻
9. fix up an electric wire 安装电线
10. ring the building firm 给建筑公司打电话
11. as it is / was 事实上，既然如此，就目前这样子看，根据现在的情况看
As it is , we can hardly get to the station by 6 o\'clock . 事实上，我们 6 点前是很难赶到车站的。
She agreed to buy the house as it is . 她同意照房子原样买下来。
I thought things would get better , but as it is they are getting worse and worse . 我原来以为情况会好转，但现在看来，情况是越来越恶化。
Don\'t do anything to make the situation worse ; it\'s bad enough as it is . 不要再火上加油了，现在情况就够糟的了。
12. report on 对……进行报道
13. one\'s first visit to + 地点 “对……的第一次访问”。
He will never forget his first visit to China .
14. at war 处于战争状态，处于交战状态
At that time China was at war with Japan . 当时，中国正与日本交战。
注意这里介词 at 后没有冠词 the 。类似的表达还有：at desk 在工作，at table 在用餐，at work在上班，at sea 在海上，at + 名词
针对练习：
1) When he writes , he always keeps a dictionary （在手边）.
2) My family and I were ____ (吃饭) when somebody knocked at the door .
3) Don\'t be nervous . Make yourself ____ (无拘无束) .
4) ____ (目前) I\'m very busy . Let\'s discuss it sometime next week .
5) His manners are rough , but he is a kind man (在内心里) .
6) It\'s ten o\'clock (晚上) .
7) He is （求学）in Paris , so I\'m afraid you can\'t see him .
8) They had first met (在航海中) .
9) Wilma can play music (一见) .
10) (有时) I made mistakes when speaking English .
11) These nations were (在交战) but now they are (和好) .
12) You may come and go (随意地) .
13) Are your parents (在上班) ?
14) The baby weighed 8 pounds (在出生时) .
注意留心下列习语中的冠词有无，其意义不变：
at (the) worst 在最坏的情况下，at (the) least 至少，at (the) latest 最迟 ，at (the)most 最多
答案：1) at hand 2) at table 3) at home 4) At present 5) at heart 6) at night 7) at school 8) at sea 9) at sight 10) At times 11) at war , at peace 12) at will 13) at work 14) at birth
