题干

下列关于生物学实验操作、实验结果、实验现象及原理的描述中,正确的是(   )

A:用纸层析法分离菠菜滤液中的色素时,橙黄色的色素带距离所画滤液细线最远

B:用洋葱鳞片叶大片内表皮和动物膀胱作半透膜都能成功完成渗透作用实验

C:探究酵母菌的呼吸方式可以用是否产生二氧化碳来予以确定

D:可用斐林试剂鉴定甘蔗中的蔗糖

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A

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      The freezing Northeast hasn't been a terribly fun place to spend time this winter, so when the chance came for a weekend to Sarasota. Florida. my bags were packed before you could say “sunshine. I left for the land of warmth and vitamin C(维生素C), thinking of beaches and orange trees. When we touched down to blue skies and warm air, I sent up a small prayer of gratefulness.Swimming pools, wine tasting, and pink sunsets(at normal evening hours, not 4 in the afternoon) filled the weekend, but the best part—particularly to my taste, dulled by months of cold­weather root vegetables—was a 7 a.m. adventure to the Sarasota farmers'market that proved to be more than worth the early wake­up call.

      The market, which was founded in 1979, sets up its tents every Saturday from 7 a.m. to 1 p.m., rain or shine, along North Lemon and State streets.Baskets of perfect red strawberries; the red­painted sides of the Java Dawg coffee truck; and most of all, the tomatoes:

amazing,large,soft and round red tomatoes.

      Disappointed by many a broken, vine­ripened(蔓上成熟的) promise, I've refused to buy winter tomatoes for years. No matter how attractive they look in the store, once I get them home they're unfailingly dry, hard, and tasteless.But I homed in, with uncertainty, on one particular table at the Brown's Grove Farm's stand,full of fresh and soft tomatoes the size of my fist.These were the real deal—and at that moment, I realized that the best part of Sarasota in winter was going to be eating things that back home in New York I wouldn't be experiencing again for months.

       Delighted as I was by the tomatoes in sight, my happiness deepened when I learned that Brown's Grove Farm is one of the suppliers for Jack Dusty, a newly opened restaurant at the Sarasota Ritz Carlton, where—luckily for me—I was planning to have dinner that very night.Without even seeing the menu, I knew I'd be ordering every tomato on it.