— Learning a language isn't easy. It takes time.    

— I agree. ______. There's no short cut.   [ ]

A. All roads lead to Rome                    

B. Rome wasn't built in a day  

C. Practice makes perfect                      

D. Slow but sure wins the race

判断对比剂过敏的依据，正确的是()

A．休克

B．便秘

C．打嗝

D．恶心呕吐

E．以上都是