He became very weak towards the end of his life.

他临终时很虚弱。

《牛津词典》

He looked very weak.

他看上去很虚弱。

youdao

The economy is very weak.

经济十分萧条。

《牛津词典》

"If the monsoon basically fails or is a very weak one, the trees affected by monsoons at that location might put on a very narrow ring.

VOA: special.2010.05.25

So what we see is a bond order of 0, and again, the bond is very, very weak.

我们看到键序是0，同样的，键非常非常的弱。

麻省理工公开课 - 化学原理课程节选

and to know your weak spots and know like... just practice stuff that you're not very good at.

知道自己的弱点在哪里，知道…就练习不太擅长的那些。

收到了录取通知书 - SpeakingMax英语口语达人

Clearly, a very weak job market is the prime cause for this loss of hope.

FORBES: What American Dream?

The case for a link between malaria and global warming has always been very weak.

FORBES: Mosquitoes Ignore Global Warming Predictions

Each operation, involving 10-12 hours 'starvation' ahead of the general anaesthetic, left me very weak.

BBC: NEWS | Health | 'I never want to go into hospital again'