题目内容
陆地生态系统的主要类型有__________、__________、__________、__________、__________、__________、__________、__________。
查看答案
搜索结果不匹配？点我反馈
更多问题
(厦门大学，2000)死亡率是一种群在单位时间内__________占__________原比率。
The simple perception of natural forms is a delight. (46)The influence of the forms and actions in nature is so needful to man, that in its lowest functions, it seems to lie on the confines of commodity and beauty.To the body and mind which have been cramped by noxious work or company, nature is medicinal and restores their tone. The tradesman, the attorney comes out of the din and craft of the street and sees the sky and the woods, and is a man again. In their eternal calm, he finds himself. The health of the eye seems to demand a horizon. We are never tired, so long as we can see far enough. (47)But in other hours, Nature satisfies the soul purely by its loveliness, and without any mixture of corporeal benefit. I see the spectacle of morning from the hilltop over against my house, from daybreak to sunrise, with emotions which an angel might share.The long slender bars of cloud float like fishes in the sea of crimson light. (48)From the earth, as a shore, I look out into that silent sea. I seem to share its rapid transformations; the active enchantment reaches my dust; and I dilate and conspire with the morning wind.How does Nature deify us with a few and cheap elements! Give me health and a day, and I will make the pomp of emperors ridiculous. The dawn is my Assyria; the sunset and moonrise my Paphos, and unimaginable realm of faerie; broad noon shall be my England of the senses and the understanding; the night shall be my Germany of mystic philosophy ad dreams. Not less excellent, except for our less susceptibility in the afternoon, was the charm, last evening of a January sunset. (49)The western clouds divided and subdivided themselves into pink flakes modulated with tints of unspeakable softness, and the air has so much life and sweetness that it was a pain to come within doors.What was it that nature would say Was there no meaning in the live repose of the valley behind the mill, and which Homer or Shakespeare could not reform for me in words (50)The leafless trees become spires of flame in the sunset; with the blue cast for their background, and the stars of the dead calices of flowers, and every withered stem and stubble rimed with frost, contribute something to the mute music.
环境资源是有限的，种群不可能长期连续呈指数式增长。
Television—the most pervasive and persuasive of modern technologies, marked by rapid change and growth—is moving into a new era, an era of extraordinary (1)_____ and versatility, which promises to reshape our lives and our world. It is an electronic revolution of sorts, made possible by the (2)_____ of television and computer technologies. The word "television", derived from its Greek (tele: distant) and Latin (vision: sight) roots, can (3)_____ be interpreted as sight from distance. Very simply (4)_____, it works in this (5)_____: through a sophisticated system of electronics, television provides the capability of (6)_____ an image (focused on a special photo-conductive plate within a camera) into electronic impulses, which can be sent through a wire of cable. These impulses, when fed into a (7)_____ (television set), can then be electronically (8)_____ into that same image. Television is (9)_____ just an electronic system, (10)_____. It is a means of expression, as well as a (11)_____ for communication, and as such becomes a powerful tool for reaching other human beings. The field of television can be divided into two (12)_____ determined by its means of transmission. First, there is broadcast television, which reaches the masses through broad-based airwave transmission of television (13)_____. Second, there is non-broadcast television, which provides for the needs of individuals or (14)_____ interest groups through controlled transmission techniques. Traditionally, television has been a (15)_____ of the masses. We are most familiar with broadcast television (16)_____ it has been with us for about thirty-seven years in a form similar to what exists today. During those years, it has been controlled, for the most part, by the broadcast networks. ABC, NBC and CBS, who have been the (17)_____ purveyors of news, information, and entertainment. These giants of (18)_____ have actually shaped not only television but our perception of it as well. We have come to (19)_____ the picture tube as a source of entertainment, placing our role in this (20)_____ medium as the passive viewer.
微信支付 
支付宝支付