影响液体与气体可燃物自然点的因素是（）。A、压力 B、浓度 C、氧含量 D、催化剂

I like sports very much. I have 5 __46__ (篮球) and 4 baseballs. Do you __47_ (知道) where they are. They’re under my bed on the __48__ (地板). I have a __49__（兄弟）.__50__ （他）name is Peter, he likes volleyballs. He has a __51__ (大的) volleyball collection. He thinks it is __52__ (有趣的). He plays it  __53__  (每个) day at __54__ (学校) with his __55__ (朋友们).

About fifty years ago, plant physiologists set out to grow roots by themselves in solutions in laboratory flasks. The scientists found that the nutrition of isolated roots was quite simple. They required sugar and the usual minerals and vitamins. However, they did not require organic nitrogen compounds. These roots got along fine on mineral inorganic nitrogen. Roots are capable of making their own proteins and other organic compounds. These activities by roots require energy, of course. The process of respiration uses sugar to make the high energy compound ATP, which drives the biochemical reactions. Respiration also requires oxygen. Highly active roots require a good deal of oxygen.The study of isolated roots has provided an understanding of the relationship between shoots and roots in intact plants. The leaves of the shoots provide the roots with sugar and vitamins, and the roots provide the shoots with water and minerals. In addition, roots can provide the shoots with organic nitrogen compounds. This comes in handy for the growth of buds in the early spring when leaves are not yet functioning. Once leaves begin photosynthesizing, they produce protein, but only mature leaves can "export" protein to the rest of the plant in the form of amino acids.

Roots have the ability to________.

A．make proteins

B．obtain fresh air

C．produce inorganic nitrogen

D．carry out activities without energy

下列哪些属于我国开设的特定目的课税（）.

A.城镇土地使用税

B.土地增值税

C.耕地占用税

D.筵席税

E.城市维护建设税

对于无代价抵偿货物的税、证管理规定，下列表述中错误的是：

A．如属国家限制进口商品，与原货品名、数量、价值、贸易方式一样，无论原货是否退运境外，均可免予另办许可证件
B．对外商同意因残损而削价并补偿进口的同品名、同规格货物，如价格未超过削价金额的，可免税
C．对于车辆、家电等无代价抵偿货物，进口时可免税，但其留在国内的原货应视其残损程度估价纳税
D．抵偿货物进口申报时，除进口货物报关单外，应随附原进口货物报关单、税款缴纳证、商检证书或索赔协议书

儿科疾病特征表述有误的是（）

A.各年龄阶段儿童患病种类不同

B.与成人疾病种类有很大不同

C.小儿对致病因素所致的病理反应与成人相同

D.免疫系统未完善，防御疾病能力差