1.collateral n.抵押品，担保(property pledged by a borrower to protect the interests of the lender)

词根记忆：col+later(边)+al--需要一边提供支持的--担保

例:I have no collateraL so the bank probably won't give me a loan.

同根词：bilateral(a．双边的)；equilataral(a．等边的)

2.collective a．集体的（relating to a group or society as a whole)

例:Using our collective resources, we made a bid for the property.

派生词:collectively( ad.全体地，共同地)

3.collide v.碰撞：抵触(to clash)

例:Two planes collided in midair.

派生词:collision(n．碰撞；冲突)

4.collinear a．在同一直线上的(passing through or lying on the same straight line)

词根记忆：col(一起)+linear(直线的)--在同一直线上的

例:Three or more points Pl, P2, P3.…., are said to be collinear if they lie on a single straight line L.

5.colonize v.建立殖民地，拓殖(to establish a colony in an area)

词根记忆：来自colony(n.殖民地)

例:An ancestral species might have adapted to exploit a particular ecological niche on one island and then traveled over water to colonize other islands.

派生词:colonization(n.殖民；殖民化)

6.coloration n．着色法，桨色法( the method of dying)；颜色，色泽(color)

词根记忆：来自color(n.颜色)

例:Studies of several animal species have shown that when choosing mates,females prefer males with brighter carotenoid-based coloration.

7.colossal a．巨大的，庞大的(enormous)

例:Buying computers for an entire company is a colossalexpense.

8.combat n.战斗(war, conflict)；v.与…作战；同…斗争(to struggle against);a．战斗的

词根记忆：com+bat(打，战斗)--战斗

例:To combat this problem we must establish a board to censor certain movies．//the combat mortality rates战斗死亡率

派生词：combatant(n．参战者，战士)：combative(a．斗志旺盛的)

同根词：baton(n.警棍)；acrobat(n.杂技演员)

9.combine v.联合，结合(to join)

词根记忆：com(共同)+bi(两个)+ne--使两个在一起--结合

例:Mexican American leaders combined ethnic with contemporary civic symbols.

派生词：combined(a．组合的)；combination(b.组合，化合)

10.combustion n.燃烧(burning, catching fire)

词根记忆：com+bust(燃烧)+ion--燃烧

例:The quick combustion of the dry forest was caused by the lack of rain.