rudimentary

这个部落仍然使用原始的狩猎工具。

The tribe still uses ___rudimentary hunting tools.

他只掌握了这门语言的初步知识。

He has only a ___rudimentary grasp of the language.

这个想法还处于雏形阶段，需要进一步完善。

The idea is still in its ___rudimentary stage and requires further refinement.