Investors can 51_______ money simply by loaning it. The money they loan is called capital. Security (担保) is an expensive item which the borrower mortgages (抵押) to the investor to show that he intends to 52_______ the debt. The way investors make money on loans is to charge interest. Interest is money that 53_______ pay to investors for the use of their money. Interest is usually a certain percentage of the capital. Investors sometimes 54________ ten percent or more interest per year. The interest may be calculated daily， monthly， or yearly. The interest must be 55_______ before the capital can be repaid. If the interest is not 56_______ the agreed rate， the interest is added 57_______ the capital. Then the borrower has 58_______ pay interest on the unpaid interest 59_______ on the capital. A debt can grow quickly this way. If the total of the capital and accumulated interest gets too high， the investor will take 60_______ of the item used as security and sell it to get his money back.