缺乏叶酸和维生素B12发生贫血的主要机制是A．影响DNA合成，使红细胞生成速度减慢

Farming in the USA today is very different from that 100 years ago. In those days, farmers did not have many machines to help them. They had animals. 小题1:____This meant that farms were smaller than they are now. Farmers also worked in a different way in the past. In those days, farmers grew fruits and vegetables and kept cows, pigs and chickens to feed their families. 小题2:______.Farmers have a very special life in many ways. First of all, they can’t leave the job at the end of the day. They live on the farm and there is always work to do. Second, a lot of farm work is outdoors, so the weather is very important for farmers.小题3:A lot of bad weather means farmers will lose money. Finally, farmers work with  plants and animals. They understand nature better than other people do.Farm work changes with the seasons. Spring is a time for planting. Farmers are busy getting the fields ready and then planting the seeds(种子). In summer, farmers must take good care of the plants. Some may need water. Other plants may have problems with insects or diseases. Then in eady for picking. 小题4:_____. Winter is a time for rest or for work on the farm machines.

A．It is also important for the success of their farms

B．So all the farmers are happy to get them

C．Today farmers grow things on the farms, so they can sell them for money

D．But animals work slowly compared to machinesE. That is a very busy time for farmers

It can not be used before( )

A．inspect

B．insoected

C．being inspected

D．inspecting

男性，4岁，口干多饮，不喜进食，皮肤干燥，缺乏润泽，舌红少津，大便干。

此患儿之厌食的治法是（）

A.调脾助运

B.养胃生津

C.健脾益气

D.调和脾胃

E.以上都不是

男性，63岁，腹胀、双下肢浮肿、乏力、食欲不振，影像所见如下图，最佳的诊断是（）

A.酒精性肝硬化

B.血吸虫肝硬化

C.肝炎后肝硬化

D.局限性脂肪肝

E.原发性肝癌

钢轨焊缝的气孔缺陷发生在（）焊缝。