Mary was born in 1998 and she began to play guitar at the age of seven.A.a B.不填C.the

问题补充：

Mary was born in 1998 and she began to play guitar at the age of seven.

A.a B.不填C.the

答案：

解析：西洋乐器前面要用定冠词the，所以应该是play the guitar.故选C.