The Sun's spots, which they had known about for years,seemed to have unexpectedly vanished.人們知道太陽黑子已有多年，但它們出人意料地消失了

know about知道； 了解； 聽說過有關 ... 的情況

I'd love to know about the plan.

我想知道這個計劃。

This is all I know about it; for the rest, you may ask others.

對這件事我就知道這些，至于其他情況，你可以問別人。

There were people who carried on looking for sun spots for 50 years,有人繼續尋找太陽黑子觀測了五十年

carry on繼續進行；從事，經營

We'll carry on our conversation tomorrow.

我們明天將繼續進行會談。

look for尋找；尋求

He turned on the torch to look for his keys.

他打開了手電筒，尋找鑰匙。

As the tide receded we were able to look for shells.

潮水退去，我們就能尋找貝殼了。