煤炭产业部门和电力产业部门是一种单向联系方式。

呼吸性酸中毒时，血浆中Cl^-水平（）

A.升高

B.降低

C.不变

D.与血红蛋白结合

E.与清蛋白结合

确定垂直距离是为了（）

A.使患者恢复年轻时的面部形态

B.较好的发挥咀嚼肌的力量

C.排牙方便

D.选择人工牙

E.达到平衡

患者，男性，24岁。主诉：牙龈疼痛伴出血3天。检查：牙龈缘充血、水肿，龈 * * 变平，探诊易出血，有腐败性口臭。此患者最可能的诊断是（）

A.牙间 * * 炎

B.边缘性龈炎

C.牙龈纤维瘤病

D.青少年牙周炎

E.急性坏死性龈炎

FREEZING FOOD　　The discovery of freezing has changed our eating habits more than any other related invention. Because many foods contain large amounts of water, they freeze solidly at or just below 32 degrees Fahrenheit. When we lower the temperature to well below the freezing point and prevent air from penetrating the food, we retard the natural process of decay that causes food to spoil. Freezing preserves the flavor and nutrients of food better than any other preservation method. When properly prepared and packed, foods and vegetables can be stored in the freezer for one year.　　Most vegetables and some fruits need blanching before they are frozen, and to avoid this step would be an expensive mistake. The result would be a product largely devoid of vitamins and minerals. Proper blanching curtails the enzyme action, which vegetables require during their growth and ripening but which continues after maturation and will lead to decay unless it is almost entirely stopped by blanching. This process is done in two ways, either by plunging vegetables in a large amount of rapidly boiling water for a few minutes or by steaming them. For steam blanching, it is important that timing begin when the water at the bottom of the pot is boiling. Different vegetables require different blanching times, and specified times for each vegetable must be observed. Under-blanching is like no blanching at all, and over-blanching, while stopping the enzyme action, will produce soggy, discolored vegetables.

Why does the author mention 32 degrees Fahrenheit

A．To suggest the storage temperature for most foods

B．To identify the freezing point of water

C．To state the correct setting for a freezer

D．To give the temperature for blanching

人的典型的气质类型一般有多血质、（）、（）和（）四种。