The fourth condition, however, is rather tricky.

但是，实现第四个条件很需要技巧。

youdao

However, under the terms of the tender, the initial 18 jets must be supplied in a fly-away condition between the third and fourth year of signing of the contract, he said.

WSJ: India Still to Finalize Terms for Jet Deal With Dassault

The Condition of Education 2006, a report published by the NCES, had our fourth graders scoring twelfth in the world in math skills, after such nations as Singapore, Latvia, and Hungary.

NPR: Seeking Solutions for the Nation's Broken Schools