They have been woking on this project for one month. It seems they need ________ month to finish it.
Not until I went to America _________ what kind of country it was.
_________ forget my hometown and my happy childhood.
_________ she would have avoided the accident.
Seldom _________ any mistakes during my past five years of teaching in this university.
It was _________ he said _________ disappointed me at that time.