【判断题】开放文明环境地图项目只是一个公益环保项目,与经济学无关。()
【单选题】Where did Tom go last summer? --- He __________ have a chance to visit Hong Kong Disneyland last summer. A. was enough lucky to B. was lucky enough to D. was lucky to enough
【判断题】环己醇催化脱水合成环己烯过程中,反应最终馏出液用饱和食盐水置换水层后,上层为有机相。( )
【单选题】下列说法中,正确的是 。
B.
作用在刚体上的力的三要素是大小、方向、作用线
C.
若作用在刚体上的三个力共面且汇交于一点,则此三力平衡