某企业距其企业章程规定的经营期限只剩5年，到期后不再继续经营。预计未来5年的预期收益

Ⅳ度根分叉区病变，最不需做哪项治疗（）

A.牙龈切除术

B.牙周翻瓣手术

C.洁治术

D.刮治术

E.根面平整术

（10分）某澄清溶液中，可能含有NH₄^＋、Mg²⁺、Na^＋、Fe^2＋、Ag^＋、OH^－、Cl^－、I^－、NO₃^－和SO₄^2－等离子中的几种，现进行如下实验：

（1）用pH试纸检验时，试纸呈深红色。

（2）取溶液少许，加入足量CCl₄，在不断振荡的条件下加入足量氯水，静置，上层接近无色，下层呈紫色。

（3）向（2）所得水溶液中加入AgNO₃溶液，有白色沉淀生成。

（4）另取原溶液，调节pH使其呈中性后，滴加NaOH溶液，开始得白色沉淀；接着加入过量NaOH溶液，过滤后给滤液加热，有刺激性气味的气体产生。

（一）由此判断原溶液中一定有大量的                离子。

（二）判断有无I^-所应用的反应的离子方程式是                                  

（三）判断有无Mg²⁺所应用的反应的离子方程式是                               

（四）在不能确定的离子中，如何检验其中的阳离子？写出试验名称及判断依据的现象。

慧眼辨对错。（对的打“√”，错的打“×”）

（1）等底面积，等高的圆柱与长方体体积相等。[ ]

（2）圆柱只有一条高。[ ]

（3）当圆柱的高和底面直径相等时，圆柱的侧面展开图是一个正方形。[ ]

（4）把一个圆柱体削成一个最大的圆锥体，圆柱的体积比圆锥的体积多2倍。[ ]

（5）一个圆柱的高不变，底面半径扩大到原来的3倍，它的侧面积就扩大到原来的3倍。[ ]

按照英美法的解释，一项有效的对价必须具备哪些要件？

Counselor: Every year a popular newsmagazine publishes a list of United States colleges, ranking them according to an overall numerical score that is a composite of ratings according to several criteria. However, the overall scores generally should not be used by students as the basis for deciding to which colleges to apply.
Which of the following, if true, most helps to justify the counselor’s recommendation

A．The vast majority of people who purchase the magazine in which the list appears are not college-bound students.

B．Colleges that are ranked highest in the magazine’s list use this fact in advertisements aimed at attracting students.

C．The rankings seldom change from one year to the next.

D．The significance that particular criteria have for any two students is likely to differ according to the students’ differing needs.

E．(E) Some college students who are pleased with their schools considered the magazine’s rankings before deciding which college to attend.