如果收入15元记作+15元,那么支出20元记作( )元.
A:+5
B:+20
C:﹣5
D:﹣20
① The book is mine. ____ A. It's Mike's book.
② The book is Amy's. ____ B. The book is theirs.
③ It's their book. ____ C. Its' Amy's book.
④ The book is Mike's. ____ D. It's my book.
在4次独立试验中,事件A出现的概率相同,若事件A至少发生1次的概率是6581,则事件A在一次试验中出现的概率是()