单项选择题
In order to find an approach ______ with the inconvenient, a world conference net and agreedupon a universal system of standard time.
单项选择题 In the future, people will mainly depend on ______ energy.
单项选择题 They agreed to order ______ the waiter recommended to them.
单项选择题 ______ everyone gets a headache now and then.
