So difficult_____it to acquire a large vocabulary without the help of a teacher that he was close to giving up .
He kept looking at her, wondering whether he her somewhere.
---How long has your brother been working here? ---_______ he graduated from college in 2007.
Tom insisted what he said ______ true, but we insisted that he _____ and have a look.
I’d prefer ______ in the office rather than ______ at home watching TV.
Half an hour has been made full ______ of _____ the problem.