常用的增溶剂分为（）、（）、（）三型。常用的助溶剂有（）类、（）类两类。 发布时间：2017-06-24 17:37 │ 来源：www.tikuol.com 题型：填空题 问题： 常用的增溶剂分为（）、（）、（）三型。常用的助溶剂有（）类、（）类两类。
题型：填空题 阅读理解。 Since the earliest times, trees have always been very useful and important to man who made use of them in many ways. Even today trees continue to serve man in many ways. Trees provide man with fruits and building materials in the form of wood. Without trees it would be impossible to build houses, boats and even bridges. Furniture such as tables, chairs and beds is made of wood. In the tropics (热带地区) where it is very hot all through the year, trees protect man from the terrible heat. They are also useful.in preventing good and rich top soil from being washed away during heavyrains which are so common in the tropics. If there were no trees or vegetation (植被) of some kinds to hold back the soil with their roots, heavy rains would wash away the rich surface soil that is so importantand necessary to agriculture. The result is that the land becomes a desert. There are so many desert areas in the world. A long time ago these desert areas must have been very rich fertile (肥沃的) areas, but since our ancestors (祖先) in the distant past had no enough knowledge about science of nature, they cut down all the trees in the areas where they lived and never planted new ones. By and by, the rich surface soil was blown away and washed away by strong wind and heavy rain. In the end the land was turned into useless deserts where nothing could grow. 1. Trees provide ______ in the form of wood [ ]A. man with housesB. man with fruits and building materials C. people with bridges D. people with boats 2. ______ are made of wood. [ ]A. Building materials B. Old houses C. Chairs and beds D. New fruits 3. Trees protect man from ______ in the tropics. [ ]A. heavy rainB. good and rich top soilC. being washed away D. the terrible heat 4. If there were no trees or vegetation to hold back the soil with their roots, ______. [ ]A. the land would be richerB. many plants could growC. heavy rains would wash away the rich surface soil D. the land would not be turned into useless deserts 5. Because trees were cut down, ______. [ ]A. the soil became richerB. the land was turned into useless deserts C. new trees were planted on the land D. the land was washed away by strong winds 查看答案
题型：填空题 男，32岁，左下腹痛1年，伴腹泻，每日便3～5次，间断便血，常有里急后重。检查：血沉快；粪便镜下有红细胞和脓细胞；结肠镜检查发现结肠黏膜血管纹理模糊，表面呈细颗粒状，脆性增加伴糜烂。需行紧急手术的指征是A．腹痛加重B．并发结肠癌变C．并发中毒性巨结肠D．内科治疗无效 查看答案