-----Did you find the missing couple in the mountain yesterday?-------No, but we _ to get in touch with them ever since.A have tried B. had tried C. have been trying D. had been trying
Is it the years____you worked in the factory_____have a great effect on your literary works?
Some medicine, when wrongly____,can kill a person.
What terrible weather! It_____heavily for as long as eight hours.
His mother always keeps telling him to ______ his table manners.
This is the very dictionary____which Mr. Smith came here the other day.