题目内容：

please help me to understand this sentence 654
The average rate they earn on their investment rises only slowly as old contract mature and new ones are make,but they must either pay higher rate to hold on to their deposits or accept wide-scale withdrawals that could easily bring about insolvency.

优质解答

就在那旧的合同到期和新的合同将要签的时候,他们平均投资赚回的速率是上升缓慢的,而且他们必须付出更高的价格来保住他们的投资或同意能使他们破产的
昂贵的赔偿金.