He is organized and is often . I hope he will have more at his business.
A:success; successful
B:successful; success
C:successfully; successful
D:successful; successful
如图,OE平分∠AOB,且EC⊥OA,ED⊥OB,垂足分别是C、D.
(1)求证∠1=∠2;
(2)求证:OE是线段CD的垂直平分线.
关于热力学定律,下列说法正确的是( )