The maths problem is ______ hard for us ______ solve.
--- It’s dangerous to swim here. Look at the sign. --- Oh, I notice it. Thanks for telling me.
My brother _______ an English teacher in ten years.
Don’t shout at him. He _______.
---Oh, Mrs. King, your dress looks nice. Is it new?---No, I ______it since two years ago.
-----I called you yesterday evening, but you were not in.-----Sorry, I _____ in the shop with my mother.