The constraints concerned here are two UG principles — Subjacency and Empty Category Principle (ECP).

这限制条件是承接原则和空范畴原则。

The two main principles of the theory adopted in this paper are the Subjacency condition and the ECP, which will help us to know better of the idea we are introducing here.

本文认为汉语中并不存和一般生成语法文献中所论述接应代词相同，而帮助我们深入认识汉语某些句法性质。