在自然环境中，下面各类型生态系统中枯枝落叶层最厚的是：（）。 A.温带草地 B.北方

相传宋朝文学家苏东坡有一次画了一幅《百鸟归巢》，并且给这幅画题了一首诗：天生一只又一只，三四五六七八只，凤凰何少鸟何多，啄尽人间千石谷．这首诗既然是题“百鸟图”，全诗却不见“百”字的踪影，你也许会问，画中到底是100只鸟还是8只鸟呢？不要急，请把诗中出现的数字写成一行：

1    1    3    4    5    6    7    8

然后，你动动脑筋，在这些数字之间加上适当的运算符号就会有100出现了，应该加上哪些运算符号呢？

“他打算去买菜”和“他买菜去”中的谓语部分分别是（）短语。

A、述宾、连动

B、连动、连动

C、述宾、述宾

D、连动、述宾

下列选项中，哪一项是我国的国体

A． * * 党的领导

B．统一战线

C．工农联盟

D．人民民主专政

病毒性肺炎最常见的病因是（）

A.腺病毒

B.流感病毒

C.副流感病毒

D.冠状病毒

E.呼吸道合胞病毒

In the United States, older people rarely live with their adult children. But in many other cultures children are expected to care (1) their aged parents. In some parts of Italy, the percentage of adult children who (2) with their parents (3) 65 to 70 percent. In Thailand, too, children are expected to take care of their elderly parents; few Thai elderly live (4) . What explains these differences in living arrangements (5) cultures Modernization theory (6) the extended family household to low levels of economic development. In traditional societies, the elderly live with their children in large extended family units for economic reasons. But with modernization, children move to urban areas, leaving old people (7) in (8) rural areas. Yet modernization theory cannot explain why extended family households were never common in the United States or England, or why families in Italy, which is fully modernized, (9) a p tradition of intergenerational living. Clearly, economic development alone cannot explain (10) living arrangements. Another theory associated intergenerational living arrangements with inheritance patterns. In some cultures, the stem family pattern of inheritance (11) . (12) this system, parents live with a married child, usually the oldest son, who then (13) their property when they die. The stem family system was once common in Japan, but changes in inheritance laws, (14) broader social changes brought (15) by industrialization and urbanization, have (16) the (17) .In 1960 about 80 percent of Japanese over 65 lived with their children; by 1990 only 60 percent did-a figure that is still high (18) U.S. standards, but which has been (19) steadily. In Korea, too, traditional living arrangements are (20) : the percentage of aged Koreans who live with a son declined from 77 percent in 1984 to 50 percent just 10 years later. Although most elderly Koreans still expect to live with a son, their adult children do not expect to live with their children when they grow old.

（12）是（）

A.at

B.under

C.by

D.over