涨价预备费的计算基数是（）。A．分年的工程用费 B．基本预备费 C．设备及工器具购置

数轴上到原点的距离小于3的整数的个数为x，不大于3的正整数的个数为y，等于3的整数的个数为z，求： x+y+z的值。

基础训练篇（16）

We must have water to live. __ 1________the water we use is clean and fresh, it will make us ill. The animals __ 2________ (live) in and around lakes and rivers must also have clean water. Our rivers and lakes supply most of our water. The clear, blue water found by the first American settlers has changed. Many of our water sources are now __ 3________. They are filled __ 4________ dirt and waste which cannot be cleaned out. In many places, water is not safe for us to use.

Lake Erie was __ 5________ a beautiful lake. Now it has been called “a dying lake”. Waste from nearby homes and factories has been dumped into __ 6________. Fish can no longer live in much of its polluted water. George Washington once called the Potomac “__ 7________ finest river in the world”. Now its water is no longer blue. Instead, it is soupy green. Suds(肥皂泡沫), from detergents（洗涤剂；洗衣粉） used to wash clothes, often cover the water of our rivers.

Water cannot __8___________(make) in a factory. Once water is polluted, it is __ 9________ to make it clean and safe again. We must learn to take care of the water __ 10_______ we now have.

简述龚自珍政论和史论创作的特点。

前屈位颈椎牵引一般采用颈椎前屈角度为（）。

A、20～30度

B、10～30度

C、10～20度

D、10～40度

E、20～40度

材料一《西方文明史》中写道：大约在1660～1789年，西欧专制主义盛行，欧洲智力和文化的历史也经历了中世纪以来最重大的变化。——《西方文明史》

材料二17世纪整个欧洲大陆处于宗教迫害之中，反映自由、民主和科学的新思想被当作“异端”“邪说”而受压制，不少有发明创造的科技人才被处罚。与此同时，战争也连绵不断，法国处于内战和向外扩展的连年战争中，意大利四分五裂……这样，就使科学人才纷纷流向地处欧洲边缘而较稳定的英伦三岛。1740年经英国政府批准的实用专利只有4件，1750年为7件，1760年又增加了4件。——《英国经济史编》

材料三

依据材料三指出从图一到图二交通工具在动力上发生了怎样的变化？与这一变化密切相关的新能源是什么？指出当时这种新能源的应用对世界经济发展有哪些影响？