...5.这题的答案是would not have fallen,而我觉得是would not fall, 从句是对过去情况的虚拟倒装if the…scientists had not…,但主句用的是since+时间点,不应该是表示是从2015年到现在吗?有since的地方大都用用现在完成时,应该是指的是现在...
The outgoing U.S. president was overcome with emotion as his wife paid tribute to his decades of service during a party on the South Lawn thanking Democratic supporters and donors.中thanking修饰谁?是定语还是状语