题目

下列物质中，属于电解质的是（ ） A. SO2B. Cl2C. BaSO4D. 稀硫酸 答案：C—Why _______ let Tom go to the supermarket with us?—Sorry, he ________ his homework yet.A. you don’t; has finished B. don't; has finishedC. not to; didn’t finish D. not; hasn’t finished