Help a finance term, XDF-S5-23

isuffering

23. As more and more people invest their money in savings certificates or money-market funds in order to earn higher interest, they are abandoning traditional low-interest investment havens such as passbook accounts and life insurance policies.

(A) As more and more people invest their money
(B) While people have more and more been investing their money
(C) As money is more and more invested by people
(D) More and more, when investors put their money
(E) While, more and more, investors have been putting their money

I know the answer should be A.

But I want to know what is  " savings certificates "(储蓄券) here?

My knowledge of Finance is much limited.

Can any NN help explain the term and give full practical examples?

Thanks in advance.

[此贴子已经被作者于2003-7-1 19:39:23编辑过]