It is reported that between the year 1550 and 1950 about one kind of living things___each year

Nobody can achieve anything of real significance _____ he works very hard

Mary is a(n) painter .—So she is . She won a national award at the age of fifteen .

I might fail, but _____ I insist on doing it I don’t mind it [ ]

It’s easy ________ you to say sorry, but remember __________ be late again.