The Group of Eight (G8) ______ the richest eight countries in the world.
A beam of light will not bend round corners unless______to do so with the help of a reflecting device .
Bad luck .Our maths teacher keeps us ______too much homework.
He ______to catch the last bus but she was too late .
----Doesn’t she work here ? ----________.
----Have you learned English before ? ----Yes,I _____English for 6 years in my hometown .