单项选择题 Merry Airlines just announced that Flight 101 ______ for London has been cancelled due to a severe hurricane that is developing in the Pacific.

单项选择题 We have always laid ______ on maintaining the most professional standards when conducting business with our associates.

单项选择题 The personnel manager makes it clear that for security reasons, no one is allowed to enter the building ______ presenting a photo ID card.