题目内容：

阅读下面材料，在空白处填入适当内容（1个单词）或括号内单词的适当形式。

Two new satellites of the BeiDou Navigation (导航) Satellite System (BDS)1.(send) into space from the Xichang Satellite Launch Center in Sichuan Province on November 19, 2018.

The satellites entered the orbk2.(safe) more than three hours later and will work with 17 other BDS-3 satellites already in space. They are also the 42nd and 43rd3.(member) of the BDS satellite family. China launched these satellites with4.aim of providing navigation services for countries and regions5.participate in the Belt and Road Initiative（倡议） by the end of 2018. This is a key step for BDS developing6.a Chinese experimental system to a regional and then a7.(globe) navigation system. The positioning8.(accurate) of the BDS-3 system has been improved to 5 meters.9.(name) after the Chinese term for the Plough（北斗七星），the BeiDou system has been serving China for 18 years. The system is expected 10.(provide) first-class servlces around the globe by the end of 2020.