The number of the teachers in our school ( is ) about forty.括号中为什么填 is 不填 are

the number of造句 the number of造句 the reciprocal of number the number of中文 the number of 是什么意思? the number of同义词 The number of students Number of the black a number of the number of the number of,a small number of,a number of. the number of、a number of、large number的区别 翻译the system of number The total number of 中文 the number of的用法 a number of the students What’s the number of The number of errors( )surprising the number of revolutions是什么意思?