【名词&注释】
金属表面(metal surface)、单色光(monochromatic light)、感受器(receptor)、光电子、入球小动脉(arteriola glomerularis afferensta)、出球小动脉(efferent glomerular arteriole)、咖啡色(coffee)
[单选题]One thing he felt regret for was that he never had the________of heating him play the piano.
A. occassion
B. possibility
C. opportunity
D. chance
根据以下内容,回答下面的题目。Insure means to protect _51_ a loss of money.Most people can budget their money so that their income will cover expected expenses _52_ food, clothing, housing, and public services.But, there is no way to know _53_ who will suffer a crisis (危机) such as a serious illness, fire, flood, or a car accident.Such crises usually _54_ great expense.Even if people could predict crises, it would be hard to save enough money to _55_ the expenses.Insurance is a system _56_ a company collects money from many individuals and then pays certain expenses whenever one of those insured individuals is faced with a certain crisis.An insurance policy _57_ how much the insurance costs and how much the company will pay when a policy holder is faced with a certain crisis.There are many different kinds of insurance, _58_ hospital, motor-car and fire.Insurance can be rather expensive but most people buy insurance of some kinD.Insurance is something _59_ people buy and hope they will _60_ need._________