在甲、乙两根相同的玻璃管中分别装有质量相同的不同液体,将甲管倾斜放置、乙管竖直放置,如图所示.当两管中的液面恰好相平时( )
-- Are you going to Sam's birthday party the day after tomorrow?
-- I'm not sure. I will go with you if I _______.