题目

下列关于硅及其化合物叙述正确的是（ ） A. 硅晶体可用于制造光导纤维 B. 陶瓷、玻璃、水泥都是硅酸盐产品 C. 二氧化硅在电子工业中是重要的半导体材料 D. 二氧化硅与氢氟酸和氢氧化钠均能反应，属于两性氧化物 答案：【答案】B 【解析】 【详解】A.二氧化硅晶体可用于制造光导纤维，故A错误； B.玻璃的主要原料是纯碱、石灰石、石英，水泥的主要原料是黏土、石灰石，陶瓷的主要原料是黏土，石英的主要成分是二氧化硅，黏土属于硅酸盐，故都是硅酸盐产品，故B正确； C.晶体硅是半导体材料，而不是二氧化硅，故For thousands of years, man has enjoyed the taste of apples. Apples, which are about 85 percent water, grow almost everywhere in the world but the hottest and coldest areas (地区). Among the leading countries in apple production are China, France and the United States.There are various kinds of apples, but a very few make up the majority of those grown for sale. The three most common kinds grown in the United States are Delicious, golden Delicious, and McIntosh.　Apples are different in colour, size, and taste. The colour of the skin may be red, green, or yellow. They have various sizes, with Delicious apples being among the largest. The taste may be sweet or tart (酸的). Generally, sweet apples are eaten fresh while tart apples are used to make applesauce (苹果酱).　Apple trees may grow as tall as twelve metres. They do best in areas that have very cold winters. Although no fruit is yielded during the winter, this cold period is good for the tree1.It can be learned from the text that delicious apples are _______________A.grown in FranceB.sold everywhereC.very bigD.quite sweet2.Cold winter weather is good for _______________A.the growth of apple treesB.producing large applesC.improving the taste of applesD.the increase of water in apples3.China, France and the United States are considered to _______________A.be large producers of applesB.be large producers of applesauceC.have the longest history in apple productionD.have the coldest winter among apple producing countries