I ________ with all the windows closed, but now I’d like some fresh air.[ ]

ition to the farming they ______ since the1990s, the Smiths have started a small business

spects of a pilot’s job __________ be boring, and pilots often__________ work at inconvenient hours

I think that studying in pairs or groups is necessary____you want to learn from each other in class.

(2013·哈尔滨四校高三统一检测)The old man often looked back on the past days ________ he worked hard to make a living.