如下图，2011年1月11日12时50分，“中国第五代隐身重型歼击机-歼20,在成都实现首飞，历时18分钟，这标志着我国隐形战斗机的研制工作掀开了新的一页” 。歼20 首次使用了我国自主研制的具有坚固、轻巧、美观、易于加工等特点的钛锂合金板材。选用这种材料与下列哪个物理属性无关 (     )

对于任意三角形的高，下列说法不正确的是（  ）

阅读，判断句子正（T）误（F）。

    Dalong is ten. He likes swimming. This is his father, He likes basketball. This is his mother. She likes table tennis and skiping. This is his sister, Lanlan, She likes skipping and swimming. She doesn't like football.