题目

High-tech machines have made life easier for millions around the world．However, some people still prefer low-tech ways of doing things．Here’s an example of why this is happening．You can microwave a frozen hamburger in 60 seconds．However, it won’t taste as good as one you cook on the stove．And if you’re in that much of a hurry, you probably won’t take time to toast the bun．High-tech cooking saves time, but it doesn’t make for better-tasting meals． Most people get their news from high-tech sources like television or the Internet．This has many advantages．For exa12．制作人体口腔上皮细胞临时装片时，选用的盐水浓度和目的依次是（　　）A．1%，作为一种染色剂B．0.65%，杀死细胞C．0.1%，使细胞变大看得更清楚D．0.9%，保持细胞原形