`XXV`:

`1.`If you don't get the visa, you can't visit the USA.

`2.`We can only get into the house if someone has key.

`3.`Unless you keep your feet dry, you will catch a cold.

`4.`If Joean doesn't find a good job before September, she will stay on at school.

`5.`Unless it rains soon, millions of pound's worth of crops will be lost.

`6.`Unless you work hard, you'll ail the exams.

`7.`If you don't save some money, you won't be able to buy the house.

`8.`Unless you behave yourself, your parents will be very unhappy.

`9.`If you don't have your hair cut, they won't let you in.

`10.`Unless you do it carefully, you will feel sorry afterwards.

`11.`If you don't ask him, he won't offer to help.

`12.`Unless you go out more often, youll fail ill.

`13.`Unless you take a hat with you, you'll be caught in the rain on the way back.

`14.`If you don't write it again more carefully, he won't be able to read it.

`15.`Unless you have another look at those lessons, you'll get bad marks.

* Giải thích :

`*`Unless `=`If...not.... : nếu không.

`-`Khi viết lại từ If về Unless, ta giữ nguyên một vế và trái vế còn lại ( vế Unless không có not )

`-`Khi chuyển từ If về Unless mà vế chứa If là phủ định thì khi chuyển sang Unless, ta sẽ bỏ "not" và chia theo thì.

`eg` : If he doesn't hurry up, he will be late.

`=`Unless he hurries up, he will be late. ( Vì "he" là chủ ngữ số ít nên hurry sẽ chuyển thành hurries )

`*`Câu mệnh lệnh : .........or........... : ....hoặc/ nếu không......

`eg` : Study hard or you will fail the exam.

`=`Unless you study hard, you will fail the exam.

`=`If you don't study hard, you will fail the exam.