It’s quite normal to ten percent of the cost of a building for a period of six months or so, in case faults are found in it.
The medicine _____ natural plants.
----- I’m going to the States. ----- How long ______ you ______ in the States?
I don’t think _____ possible to master a foreign language without much memory work.
----- My father will be here tomorrow. ----- Oh, I thought that he _____ today.
She likes playing _____ guitar while her brother is fond of playing _____ football.