Today, the contribution of service industries of the developed countries constitutes over ______ of their gross domestic products and account for an increasing proportion of world trade.
A、70%
B、40%
C、50%
D、60%
【正确答案】：D
【题目解析】：Today, the contribution of service industries of the developed countries constitutes over 60% of their gross domestic products and account for an increasing proportion of world trade.参见教材P4。