Please tell me how many letters there are in the post office?为什么要用there are 而不是 are there

问题描述:

Please tell me how many letters there are in the post office?为什么要用there are 而不是 are there
How many trees are there in the park?是使用are there ..
而问题中的句子却使用的是there are?...
可是这个明明是问人的阿?...

Please tell me后面是省略that的宾语从句,宾语从句要用陈述句语序所以用there are
How many trees are there in the park?是简单句,且是疑问句所以用are there