in the queue for half an hour, Tom suddenly realized that he had left his wallet at home.
A．To wait
B．Have waited
C．Having waited
D．To have waited
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解析：考查现在分词的完成式用法：通过分析句子，后面是主句，前面是分词做状语，因为句意是：排队等了半小时后，汤姆突然意识到他把钱包落在家里了。说明是先等了半小时才发现的，状语和主句的动作有明显的先后关系。用现在分词的完成式。选C。
考点; 考查现在分词的完成式