瓦斯监测仪在装配气室应注意检查光路是否正确,装上后要()、()、()、()、()现象,排除()。
参考答案:视场宽敞、条纹清晰、无挡光、干涉条纹弯曲、变虚现象、杂光
—Shall I get something for you? What's your favorite?
—It's very kind of you! Please don't waste _________ money. Special is the best choice. [ ]
A. many
B. too many
C. too much
D. much too
数据的独立性分为逻辑独立性与物理独立性。当数据的存储结构改变时,其逻辑结构可以不变,因此,基于逻辑结构的应用程序不必修改,这称为______。