Couldest
v. can的过去式\\nv. aux. can的过去式[在现在时或将来时的动词短语中作助动词, 表示有点怀疑或较小的可能性]能, 可能：
🗣️ 情景例句
Good night.
晚安。
What's your nationality?I'm a native Australian.
我是土生土长的澳大利亚人，你的国籍是什么？
I had nearly reached the town, when the young man suddenly said, very slowly, Do you speak English?'
“你会讲英语吗？”