老同学的英文：
old boy

参考例句：

An old school chum
老同学.

The meeting of the old classmates was extremely cordial
老同学聚会在一起,分外亲热。

I'm going to call on one of my former classmates.
我要去看望我的一位老同学。

I ran into an old schoolfriend at the supermarket this morning.
今天早上我在超级市场碰见了一个老同学.

old是什么意思：
adj. 年老的；陈旧的；古老的；以前的；原来的
n. 古时

The Old Mandarin
老官吏

You old misery!
你这个爱抱怨的老家伙！

It is an old aphorism.
这是一句老格言。

Old friends and old wine are best
朋友是旧的好;古交友情深,陈酒香味醇

Old friends and old wines are best
陈酒味醇,老友情深

boy是什么意思：
n. 少年，男孩；儿子；男仆；老弟，家伙

A boy was kidnapped.
有个男孩被拐走了。

They are clapping for that boy.
他们在给那个男孩儿鼓掌。

“Boy” is a “noun”.
男孩是个名词。

`Anne's',`the boy's',`the boys'' are possessive forms.
Anne's、the boy's、the boys'都是属有格形式.

He switched the boy.
他鞭打那男孩。