【2015·重庆】He wrote many children’ s books, nearly half of____ were published in the 1990s.
---You should say sorry to her, Tom. --- ______, but it’s not going to be easy.
Canada is a country ______ many different nationalities as well as one with foreign immigrants ______ the majority of its population.
.--- Where are you, Nancy? --- Here in the sitting room, _______ to Professor Smith.
--- Where will you start your work after graduation? --- Mmm, it’s not been decided yet.I _______ continue my study for a higher degree.
How many more decades will have to pass ____ scientists succeed in providing a cure for cancer?