unit19(參考版)
2025-07-20 18:21本頁(yè)面
【正文】 re using is 4 ft in height． We now walk farther away from the watertower in the same straight line as we have measured off the distance of 90 ft． Then we go from the spot C until we e to a point E, where with our heads on the ground we see the top of the stick and the top of the watertower in the same straight linethat is, the top of the stick just covers the highest point of the watertower． We now have two triangles (三角形 ) and the proportion (比例 ) of the side CD to the side CE in the smaller triangle CDE is exactly the same as the proportion of the side BA to the side BE in the larger traingle BAE． It is clear from this that every schoolboy or schoolgirl can work out the height of the watertower． Suppose that the line CE is 5 ft． We know that the stick is 4 ft high and the length BE is 95 ft． From these measurements we have the simple proportion sum (算式 ) 5 is to 4 as 95 is to A B． Now we can find out the height of the watertower． Trees and other high buildings, of course, can be easiy meassured by using the same way． 51． According to the passage, the height of the watertower is ______. A． 76 ft B． 95 ft C． 90 ft D． 180 ft 52． E is ______. A． a point on the ground B． a straight line on the ground C． the top of the stick D． the top of the watertower 53． The triangle CDE must be A． below the triangle BAE B． in the triangle BAE C． out of the triangle BAE D． over the triangle BAE 54． The proportion of the side CD to the side CE is ______ the proprotion of the side BA to the side BE. A． bigger than B． equal (相等的 ) to C． not as big as D． smaller than 55． From the measurement, we have the simple proportion sum ______． A． BA is to four as five is to niyfive B． BA is to niyfive as four is to five C． five is to niyfive as BA is to four D． four is to five as BA is to niy B Meat and vegetables are measured in grams(克 ) and kilograms． Milk and other liquid (液體的 ) foods are measured in litres (升 ) and millilitres (毫升 )． These units only measure quantity, they do not measure the value of the food to the body． The unit which measures the quality or value of food is the “calorie”． A calorie is the amount of heat given off by food when it burns． This measurement tells how much energy a certain food has when it is pletely used by the body． Our bodies use varying (不等的 ) amounts of calories． The more exercise we take, the more calories we burn． If we eat food which contains more calories than we use up, then it is possible that we would increase in weight． In order to
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