He started to learn English in 1990 and in the years ________ he kept on using it in his work.
--- Did you ask the guard _______ happened? --- Yes, he told me all _______ he knew.
Smoking, _______ is a bad habit, is, however, popular.
You can depend on whatever promise _______ he makes.
.He is not such a man _______ would leave his work half done.
My neigh bours used to give me a hand in time of trouble, _______ was very kind of them.