3x2-[7x-(4x-3)-2x2]
原式=3x2-[7x-4x+3-2x2]
=3x2-7x+4x-3+2x2=5x2-3x-3
小强利用爷爷的老花镜,一把刻度尺和几根火柴,硬纸板完成两个实验,请你回答下列相关问题.
(1)小强利用老花镜在阳光下,将火柴点燃了.这种现象说明:______
(2)小强利用刻度尺粗略测出老花镜的焦距,从而得知老花镜的度数,请写出测量老花镜焦距的主要步骤:______.
(3)利用老花镜你还能完成什么实验?请写1个.答:______.
In the following passage, there are 25 blanks representing words that are missing from the context. You are to put back in each of the blanks with the missing word. Write your answers on the ANSWER SHEET. The time for this section is 25 minutes. Compared with the immediate practical responsibility of the scientist, the (1) of the artist must seem puny. The decision which faces (2) is not one of practical action: of course he will try to throw this (3) into the scale, and that weight, if he is a writer or (4) a painter of genius, may have its effect. For the novelist—in our society the only artist who has a mass audience and at the same time effective economic control of the means of addressing (5) —the hope of some decisive influence is a reasonable (6) . For him, since he takes of all artists (7) is probably the largest portion of his culture as material, there is no (8) escape from the necessity for treating the content of his work seriously than (9) is for the social psychologist he is coming so closely to resemble. The dichotomy which people have tried to establish between artistic proficiency and (10) content is becoming unbearable to almost all sensitive minds. I doubt if it has ever been real— we might have admired Shelley as (11) if he had been indifferent to such things as war and tyranny, though I doubt it; certainly (12) he been indifferent we should never have been led by (13) . There is no Hippocratic oath in literature, and I am not attempting to draw (14) up. As far as I am concerned, the artist is a human being writ large and his (15) are the ethics of any human being. Perhaps I can best illustrate (16) seems to me the new (17) of those duties of assertion and refusal from one writer, and I do not (18) it is without significance that this (19) projects the whole situation of choice into a scientific parable, the (20) of a pestilence: a (21) many human (22) are called to fight against, called not by any supernatural (23) but by the simple fact that the fight against a plague is (24) like a biological human (25) .