题目

“I’m fourteen years old and know how to do it,” Jessie said. “Besides, it would help Dad out, and he won’t have to worry about it over the weekend.” Mom thought for a while and then decided to let Jessie give it a try. After all, she was at home and would keep an eye on her. Jessie already knew how to start the lawn mower(割草机) from watching her dad. Jessie checked the gas(汽油) to make sure it was full, and put on her gardening gloves to protect her hands. Mom watched from the kitchen window. Jessie really did know how to mow the lawn(草坪). She was very careful around th要想一次较精确地用量筒量出80g的酒精，应选用下列哪种规格的量筒（ρ酒精=0.8×10³kg/m3，下列各项中，前面的数值是量筒的量程，后面的数值是量简的分度值）(     ）A．50mL lmLB．100mL 2mLC．250mL 5mLD．500mL lOmL