spell something out
phrasal verb with spell verb uk/spel/ us/spel/
解释清楚;详细地说明
to explain something in a very clear way with details
The government has so far refused to spell out its plans/policies. 政府至今拒绝透露详细的计划／政策。
informal What do you mean you don't understand - do I have to spell it out for you? 你说你不明白是什么意思——需要我详细地向你解释一下吗？