| Boeing Co’s Sonic Cruiser, a proposed faster
airliner, would be mostly blended material, program director Walt Gillette said
recently. In its quest for the{{U}} (21) {{/U}}to fly 15 to 20 per cent
faster than{{U}} (22) {{/U}}airliners, the US company says about 60 per
cent of the new plane’s{{U}} (23) {{/U}}, including the wing, would be a
carbon-fiber-reinforced composite material that is lighter than aluminum for the
same{{U}} (24) {{/U}}. "Composites would{{U}} (25) {{/U}}almost all of
the airplane that you could see from the outside," Gillette said. Composites are
well regarded among aeronautical engineers and have been in{{U}} (26)
{{/U}}use since the 1970s. Each generation of planes has more composites,
and Gillette{{U}} (27) {{/U}}that about 10 per cent of Boeing’s{{U}}
(28) {{/U}}civil aircraft, the early-1990s 777, is built{{U}} A. before B. after C. when D. unless [单项选择]膝关节骨性关节炎最初始的病理损害发生于（）
A. 关节软骨 B. 关节滑膜 C. 软骨下骨 D. 十字韧带 E. 关节囊 [单选题]水平波瓣角是指（）
A.在天线辐射功率分布在主瓣最大值的两侧，功率强度下降到最大值的一半的两个方向的夹角 B.在天线辐射功率分布在主瓣最大值的两侧，功率强度下降到最大值的1/4的两个方向的夹角 C.在天线辐射功率分布在主瓣最大值的两侧，功率强度下降到最大值的3/4的两个方向的夹角 D.其它定义 [单项选择]低层、多层住宅栏杆净高不应低于（）m。
A. 0.90 B. 1.0 C. 1.05 D. 1.1 [多项选择]下列项目中，属于投资性房地产的有( )。
A. 企业已出租给合营企业的房地产 B. 已出租的房屋 C. 房地产企业持有并准备增值后出售的房屋 D. 自用房地产 E. 企业持有并准备增值后转让的土地使用权 [单选题][T]A-B-C-001 4 2 3
以下( )属于半导体。 A.琥珀 B.陶瓷 C.煤 D.锗 我来回答: 提交
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