题目

（贵州省贵阳二中2010届高三第一学期11月月考） D When I was 16 years old, I made my first visit to the United States. It wasn’t the first time I had been abroad. Like most of English children I learned French at school. And I had often been to France, so I was used to speaking a foreign language to people who didn’t understand French. But when I went to America I was really looking forward to having a nice easy holiday without any language problems.How wrong I was. The misunderstanding began at the airport. I was looking for a public telephone to give my friend Danny观察人口腔上皮细胞时，在载玻片中央滴加的液体是（ ）A．清水 B．生理盐水C．碘液 D．凉开水