he is (at)portsmouth now.为什么不用from

he will sail from Portsmouth He is _ Portsmouth now he will sail from Portsmouth .he is _Portsmouth now..A to.B 为什么he is having lunch at home now.中的having不用hasing? He is now working at a bank 请问NOW为什么可以放系动词后 那么为什么but he is now working at a bank中却用at? He is waiting at the bus stop?为什么用at,不用for? he is busy now.这句话的busy为什么不用ing形式 he is now working at a bank. He is at work now.同义句 He is working at the office now He is much (good) at maths now. The village （which） he lived in is far from here.为什么括号里不用whe