So what does that mean " signed up for? "

那么短语 signed up for 是什么意思呢？

That means signs of green plant life are beginning to show!

这意味着绿色植物生命的迹象开始显现！

Yellow is most often connected with sunshine and warmth, though on traffic signs it means that you should take caution.

虽然交通指示中黄色代表行人要小心，但大多数时候，黄色和阳光及温暖联系在一起。

Alex, what does that sign mean?

亚历克斯，那个标志是什么意思？

So I'm gonna let you guess what this sign means and you can post it in the comments below.

所以我会让你猜猜这个标志是什么意思，你可以在下面的评论中发表。