Allthechildrenshouldhavea/an------examinationiftheywanttostudyinthisschool.(entrance)------come-----served.isausualpracticeinmanyrestaurants.（first）

Question

All the children should have a/an ------examination if they want to study in this school.(entrance )
------come-----served.is a usual practice in many restaurants.（first）

Answer 1

All the children should have an entrance examination if they want to study in this school.
First come first served.is a usual practice in many restaurants.
这两句话的意思是：1）所有的孩子都要参加入学考试如果他们想要在学校学习.
解析：entrance是以元音开头,并且发音为元音音素.所以用an
2）捷足先登.（先来的会被先服务）这在许多食堂是一个惯例.
解析：不要问第二句为什么这样填哦,这已经算是一个英语谚语了,不要疑问他的语法结构很奇怪,英语谚语都这样.