题目

在测量石块的密度实验中，用天平称石块的质量，天平平衡时盘中砝码及游码的位置如图所示，石块的质量是________g。石块的体积是10 cm3，则石块的密度是_________kg/m3。 答案：【答案】 26.4 2.64×103【解析】 (1)由图知，标尺的分度值为0.2g，所以石块的质量为m＝20g5g1.4g＝26.4g；(2)则ρ＝＝2.64g/cm3＝2.64×103kg/m3. 根据句意用所给词组的适当形式填空，每个只能用一次。 1．Can you ________ in the next room? 2．It is too hard for us to ________ it ________． 3．Yesterday Millie ________ her friend in America． 4．Boys, it's your turn to ________ the classroom now． 5．You shouldn't often ________ yourself first． 6．It's cold outside．You'd better wear warm clothes, or you will ________． 7．If you want to learn English well, you must ________ speaking English ________． 8．________, I met one of my old friends．