Key resources are technical personnel and aircraft spare parts which account for the largest share of the maintenance ______.

单项选择题Material choices such as timber and steel also help to keep the house cool, while light colours have been used on the exterior surfaces to ______ heat and blend in with the surrounds.

单项选择题A pair of night birds circled above, the ______ of their wings and their weird screams penetrating the thickening mist.

单项选择题The ______ among his sisters was that he ought to marry the girl as soon as possible to avoid a scandal.

单项选择题It is unlikely that enough qualified teachers will be found unless there is ______ improvement in salaries and conditions of housing.

单项选择题They aim to ______ the maximum economic benefit from the Olympic Games.

单项选择题It is hoped that the prisoner will be released through the ______ of the president himself.

单项选择题Recent changes in climate may ______ that global warming is starting to have an effect.

单项选择题A ______ racial incident in the summer of 2003 was cause for great public and administrative concern.

单项选择题Many hunting and gathering people of the late 10th century have recently adopted some form of organized agriculture to ______ their wild food resources.

单项选择题Paul is amazingly ______ in trying to get Mary to go out with him.