搜题请搜索小程序“爱下问搜题”
问题 单项选择题 A1型题

心肌的异长调节是改变何种因素来调节心脏泵血功能的（）

A.肌浆游离Ca2+浓度

B.肌小节的初长度

C.心肌收缩能力

D.横桥连结数目

E.横桥ATP酶活性

答案

参考答案：B

单项选择题 A3型题

奶牛，5岁，发情表现正常。近3个月来，食欲体温正常，但常从 * * 中排出一些混浊黏液，发情时排出量较多，屡配不孕，冲洗子宫的回流液像淘米水。对该牛冲洗子宫时，首选的冲洗液是（）

A.5%氯化钠溶液

B.10%葡萄糖溶液

C.0.9%氯化钠溶液

D.0.01%苯扎溴铵溶液

E.0.01%高锰酸钾溶液
查看答案
单项选择题

The United States is well known for its network of major highways designed to help a driver get from one place to another in the shortest possible time.Although these wide modem roads are generally (1) and well maintained, with few sharp curves and straight sections, a direct route is not always the most (2) one. Large highways often pass (3) scenic areas and interesting small towns. Furthermore, these highways generally (4) large urban centers, which means that they become crowded with heavy traffic during rush hours, (5) the" fast, direct" route becomes a very slow route.However,there is almost always another route to take if you are not in a hurry. Not far from the (6) new" superhighways", there are often older, (7) heavily traveled roads which go through the countrvside. (8) of these are good two-lane roads ; others are uneven roads curving through the country. These secondary routes may go up steep slopes, along high cliffs, or down frightening hillside to towns (9) in deep valleys. Through these less direct routes, longer and slower, they generally go to places (10) the air is clean and scenery is beautiful, and the driver may have a chance to get a fresh, clean view of the world.

第（1）空应选择（）

A．stable

B．splendid

C．smooth

D．complicated
查看答案