tailieunhanh - Short answer and fast 6

Tham khảo tài liệu 'short answer and fast 6', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 48 Necessity mustn t needn t etc A Mustn t or needn t We use must to say that something is necessary see Unit 47 . You must be careful with those glasses. I must remember my key. Now compare mustn t and needn t. MUSTN T We use mustn t to say that something is a bad idea. You mustn t drop those glasses. They ll break. I mustn tforget my key or I won t get in. You mustn t wear your best clothes. You ll get them dirty. NEEDN T We use needn t when something is not necessary You needn t wash those glasses. They re dean. We needn t make sandwiches. There s a cafe. You needn t wear your best clothes. You can wear what you like. B Don t have to and don t need to We can use don t have to and don t need to when something is not necessary. The meaning is the same as needn t. You don t have to don t need to wash those glasses. They re clean. Mark doesn t have to doesn t need to finish the report today. He can do it at the weekend. For American usage see page 379. For the past we use didn t. The food was free. We didn t have to pay We didn t need to pay for it. C Didn t need to or needn t have Daniel hadn t booked a seat but luckily the train wasn tfull. He didn t need to stand. Trevor and Laura booked a table for dinner. But the restaurant was empty. They needn t have booked a table. DIDN T NEED TO We use didn t need to when something was not necessary. Standing was not necessary because there were seats. Mark didn t need to hurry. He had lots of time. He drove slowly along the motorway. We didn t need to go to the supermarket because we had plenty of food. Sometimes we can use didn t need to when the action Mark didn t need to hurry but he drove at top speed. NEEDN T HAVE We use needn t have a past participle for something we did which we now know was not necessary . booking a table. Mark needn t have hurried. After driving at too speed he arrived half an hour early. We needn t have gone to the supermarket. We already had a pizza for tonight. happened even though it was .