主要问题及次要问题

the main problem and the secondary problem

力所能及

within one's ability

目力所及

as far as the eye can see

他出国将及十载。

He has been abroad for almost ten years.

望尘莫及

left behind in the dust

在劳动方面我不及他。

I am no match for him at manual work.

老吾老，以及人之老

care for the elderly people in one's family, and extend that care to elderly people in other families

攻其一点，不及其余

concentrate on one part, but not be able to attend to the rest