fifteen minus five is ten为什么要用is

fifteen minus five is ten。算式15-5=10谓语动词用单数is。英语中加减乘除运算只有乘法可以用复数的谓语动词are/equal，其余都用单数is/equals。例如：

1、five and five is 10(5+5=10)

2、2 multiplied by 2 is/are 4(2*2=4)

3、10 minus five is five(10-5=5)

4、10 divided by 2 is 5 (10/2=5)

fifteen minus five is ten为什么要用is

数词的一些特殊用法

1、表示四则运算

3+6=9 Three plus six is nine.

5+5=? How much is five plus five?

10-5=5 Ten minus five is five.

4x2=8 Four times two is eight.

20÷4=5 Twenty divided by four is five.

2、表示编号

Lesson 5 (the fifth lesson) Class 3 (the third class)

Room 308 page 416

3、表示世纪、年代

（在）20世纪 (in) the 20th century

（在）30年代 (in) the thirties

（在）20世纪90年代 (in) 1990s

（在）1983年 (in) 1983

4、表示日期

（在）6月1日 (on) the first of June

(on) June the first

(on) June 1st

（在）1983年5月1日 (on) May 1st， 1983

注意点：在“年”“月”前要用介词in。在“...月...日”或“...年...月...日”前用介词on。

5、表示时刻

6:00 six o'clock 或 six

8:10 ten past eight 或 eight ten

9:45 a quarter to ten 或 nine forty-five

10:55 five to eleven 或 ten fifty-five

11:30 half past eleven 或 eleven thirty

注意点：在时刻前用介词at

6、表示岁数

She is fifteen (years old). 她15岁了。

He went to school at (the age of) seven. 他7岁上学。

7、分数、小数、百分数的表示

①分数：分数是由基数词、序数词组成。分子用基数词，分母用序数词，分子除1以外，序数词都用复数形式。

1/3 三分之一 one/a third 2/3 三分之二 two-thirds

7/10 十分之七 seven-tenths

2 2/3 二又三分之二 two and two-thirds

②小数：小数点是point，零是zero，小数点以后的数按个位基数词依次读出。

0.7 zero point seven

1、55 one point five five

13、98 thirteen point nine eight

③百分数：百分数由基数词加percent构成。

5% five percent

45% forty-five percent

350% three hundred and fifty percent

8、倍数的表示

①表示增加一倍

The output of cars has doubled.

汽车产量增加了一倍。

②表示增加两倍

The output of cars has been increased three times as against 1998.

汽车产量与1998年相比增加了两倍。

③The output of cars is three times greater than that of last year.

汽车产量比去年增加了3倍。

④表示有...几倍大

It is four times as large as Europe.

它有欧洲的四倍大。

9、“every other...”的表达方式。

every other day 每隔一天 every three days 每隔两天

every other week 每隔一周 every third day 每逢第三天