1.allowance n.允许( permission)；津贴，补助费(subsidy)
词根记忆：来自allow(矿允许)，允许拿到的或省下的钱_津贴，补助费
例:financial allowances财政津贴
2.allude v.(to)间接提到，暗指( to make indirect reference)
词根记忆：aI+lud(嬉笑)+e--在嬉笑中说--间接提到
例:The author alludes to the well-established nature of the concept of individual rights in the Anglo-Saxon tradition.
派生词:allusive(a.暗指的，影射)
同根词：ludicrous(a.可笑的，滑稽的)：elude(矿躲避)
3.alluvial a.冲积的，淤积的( made of sand, earth left by rivers or floods, esp. ina delta)
例:alluvial gold冲积金矿
4.ally v.（使）结盟（to unite）n.同盟者，同盟国(person, country, that joined with another in order to give help and support)
例:During World War ll,Great Britain allied with the United States.
派生词:alliance(n.结盟，联盟)
5.alpha n.希腊语字母表的第一个字母(A，a)
词根记忆：发音记忆
6.alter v.改变，变更(to change)
本身为词根：改变
例:The period of an organisms biological clock can be altered by environmental factors.
派生词:alteration(n.改变，变更)；alternative(a.二者择一的)
7.alternate a.交替的，更迭的((of two things) happening or foltowing one after the other regularly);v.交替，轮流(to cause to occur by turns)
词根记忆：alter(其他)+nate --可以有其他的--交替的
例:To maintain the nutrients in the soil, corn and soybeans are often planted in a field in altemate years.
8.alternative a.轮流的，交替的( atternate)；两者（或两者以上）择一的(offering or expressing a choice)；n.二中择一；供替代的选择(something which can be chosen instead)
词根记忆：alter(改变状态，其他的)+native(…的)--其他的一两者择一的
例:For most commuters who use the subway system, there is no practical attematwe public transportation available.
派生词:alternatively(ad.非此即彼；二者择一地)
同根词：alterable(a.可改变的)
9.altitude n.高度( height above sea-level)
词根记忆：alt(高)+itude--高度
例:The plane was flying at an altitude of 2,000 feet.
10.altruism n.利他主义，无私（unsetfish devotion to the welfare of others）
词根记忆：altru(其他)+ism(主义)--利他主义
例:Altruism means doing good things simply because the good things are worth doing.
派生词:altruistic(a.利他的)：altruist(n.利他主义者)