Rudimentary things are very basic or simple and are therefore unsatisfactory.
The earth surface of the courtyard extended into a kind of rudimentary kitchen.
院子的泥土地面一直延伸到一间类似简易厨房的地方。
Rudimentary knowledge includes only the simplest and most basic facts.
He had only a rudimentary knowledge of French.
他只有最基本的法语知识。