有段句子想请教
By 2006 , this summer had increased to 113,000 , which is estimated to
have added US 1.3 billion to Australia's economy in that year .
请问为何estimated to +have + pp ?
我的理由是上下句是同一时间(指2006年),所以时式应该一样
所以应该是estimated to add....而不是estimated to have added...
请问各位有何见解能替小弟解惑
谢谢

不是summer 而是number

时态是一样啊 都是完成式(直到2006这时间点)

如果时间点一样为何是"which 'is' estimated"？所以相较于现在，add的动作更先发生，因此用"to have added"