Animals ...............................................93 - 496
Automobile Travel, Highways ............................ 131- 141
Economics .............................................. 80 - 103
Educational Statistics ................................. 286- 321
Environment ............................................ 489- 496
First Aid .............................................. 1040
National Defense ....................................... 497- 510
National Parks .......................................... 747- 749
Passports ............................................... 142 -144
Patents, Copyright Laws.................................. 339- 340
Personal Finance ........................................ 55 - 79
Population, U.S ..........................................1 46-220
Presidential Elections ...................................766 -793
Social Security ...........................................56 - 61
Sports ............................................... 884- 978
Space Developments ........................................... 482
Taxation ............................................... 55 - 69
Theatre, Opera, Films .....................................470-477
Trade and Transportation ................................119- 141
United Nations ..........................................621- 624
U.S. Government ................................ 796 -800,818 -821
Washington, The Nation’s Capital......................... 688 -694

美国人口 ( )联合国

架棚时当棚腿长度不适量时如何处理（）

A.加深柱窝

B.加垫鞋板

C.更换适当棚腿

D.不做任何处理