多项选择题
Given that Triangle implements Runnable， and： Which two statements， inserted independently at both lines 35 and 41， tend to allow both threads to temporarily pause and allow the other thread to execute？（）
A.Thread.wait（）； B.Thread.join（）； C.Thread.yield（）； D.Thread.sleep（1）； E.Thread.notify（）；
多项选择题 Which three changes should be made to adapt this class to be used safely by multiple threads？（）
单项选择题 What is the result？（）
