【单选题】

Whichof the following may illustrate the difference between "competence"and

"performance" ?
A.What a person "knows" and what he / she "does"．
B.What a person "can do" and what he / she "does"．
C.What a person "does" and what he / she "knows"．
D.What a person "does" and what he / she "can do"．