£ £ £ Droplets and ice crystals behave somewhat like dust in the air made visible in a shaft of sunlight. To the casual observer,dust seems to act in a totally random fashion, moving about chaotically without fixed direction. But in fact dust particles are much larger than water droplets and they finally fall.The average size of a cloud droplet is only 0.0004 inch in diameter. It is so small that it would take sixteen hours to fall half a mile in perfectly still air,and it does not fall out of moving air at all. Only when the droplet grows to diameter of 0.008 inch or larger can it fall from the cloud. The average raindrop contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size large enough to fall out is the cause of rain and other forms of precipitation.This important growth process is called "coalescence. 

23. What is the main topic of the passage? 
(A) The mechanics of rain 
(B) The weather patterns of North America 
(C) How Earth s gravity affects agriculture 
(D) Types of clouds 

24.The word "minute in line 4 is closest in meaning to which of the following? 
(A) second 
(B) tiny 
(C) slow
(D) steady 

25 .Thc word "motion in line 5 is closest in meaning to 
(A) wind 
(B) change 
(C) movement 
(D) humidity 

26.Ice crystals do NOT immediately fall to Earth because 
(A) they are kept aloft by air currents. 
(B) they combine with other chemicals in the atmosphere 
(C) most of them evaporate 
(D) their electrical charges draw them away from the earth 

27. The word "random" in line 7 is closest in meaning to 
(A) unpredictable 
(B) perplexing 
(C) independentI 
(D) abnormal 

28.What can be inferred about drops of water larger than 0.008 inch in diameter? 
(A) They never occur. 
(B) They are not affected by the force of gravity. 
(C) In still air they would fall to earth. 
(D) In moving air they fall at a speed of thirty -two miles per hour. 

29 How much bigger is a rain drop than a cloud droplet ? 
(A) 200 times bigger 
(B) 1,000 times bigger 
(C) 100,000 times bigger 
(D) l,000,000 times bigger 

30. In this passage, what does the term "coalescence" refer to 
(A) The gathering of small clouds to form larger clouds 
(B) The growth of droplets 
(C) The effect of gravity on precipitation 
(D) The movement of dust particles in the sunlight 

£ £ £ People appear to be born to compute. The numerical skill of children develop so early and so inexorably that it is easy to imagine an internal clock of mathematical maturity guiding their growth. Not long after learning to walk and talk, they can set the table with impressive accuracy---one plate, one knife, one spoon, one fork, for each of the five chairs. Soon they are capable of noting that they have placed five knives, spoons, and forks on the table and, a hit later, that this amounts to fifteen pieces of silverware. Having thus mastered addition, they move on to subtraction. It seems almost reasonable to expect that if a child were secluded on a desert island at birth and retrieved seven years later, he or she could enter a second-grade mathematics class without any serious problems of intellectual adjustment.