题目

DHealth officials issued a waring over common energy-saving l一ghtbulbs(灯泡) after research showed some types could potentially harm the skin and may even raise the risk of cancer.A study by the Health Protection Agency (HPA) found that some eco-friendly lightbuulbs release levels of ultraviolet (UV) (紫外线) radiation that are above recognized safety limits. The agency urged people who work with lamps nearby to avoid spending more than one hour within a foot of the eco-friendly bulbs. The warning was directed at those using desk lamps for long periods, such as jewellery makers, and oth下列说法中，正确的是（ ）A．命题“若am2＜bm2，则a＜b”的逆命题是真命题B．命题“?x∈R，使得|x|＜1”的否定是：“?x∈R，都有x≤-1或x≥1”C．命题“p或q”为真命题，则命题“p”和命题“q”均为真命题D．已知x∈R，则“x＞2”是“x＞1”的必要不充分条件