题目

小明用电子秤进行如图所示的称量活动。经过一段时间后，活动1和活动2的电子秤示数都减小了。 （1） 活动1的电子秤示数减小,从微粒的角度解释其原因是。 （2） 活动2中电子秤示数减小的部分（填“等于”或“不等于”）蜡烛燃烧后生成物的总质量。 答案：【1】分子运动到空气中 【1】不等于用下列单词的正确形式填空 1.  I don’t know the correct________(pronounce) of the word. 2. The world’s population is one of the biggest_________(challenge) of the world today. 3.  I think________(speak) English is more difficult than written English. 4. Every player of the team was______ at the________(frustrate) result. 5. Don’t be afraid of_______ (make) mistakes when you speak English. 6. He thinks________. He has a___________ (different) idea. 7.  ________ (use) such a _________(fashion) mobile phone can make us look good in front of others.