look !How long _____ like this ?

look !How long _____ like this ?
-Look!How long ___like this?

-Three weeks! It's usual here that rain___without stopping these days of the year.
A has it been raining ;pours B has it raind;has poured
C is it raining;pours D does it rain;has poured
请问第二句里It's……that是强调句型吗
usual here啥意思？