这孩子的语言能力有些发育迟缓，需要特别关注。

The child's language abilities are ___under-developed and need special attention.

这个欠发达地区缺乏基本的电力供应。

This ___under-developed region lacks basic electricity supply.

这个游戏的故事情节显得不成熟，角色动机也不够明确。

The game's storyline feels ___under-developed, with unclear character motivations.