在英语中，"不要丢弃他们"可以用以下几种表达方式来表示：

"Don't discard them"
"Don't throw them away"
"Don't dispose of them"

这些表达方式都用来指导对方不要丢弃或者抛弃某些东西。

下面是一些英文例句，并提供对应的中文翻译：

"Please don't discard those old books. They might still be valuable."
(请不要丢弃那些旧书，它们可能还很有价值。)
"I can't bepeve you're going to throw away that antique vase. It's worth a lot of money."
(我真不敢相信你要丢弃那个古董花瓶，它价值很高。)
"We need to find a better way to dispose of electronic waste. It's harmful to the environment."
(我们需要找到一种更好的方式处理电子废物，它对环境有害。)