题干
My sister likes playing_____guitar and she also likes playing______soccer.
A：the; the
B：/; /
C：/; the
D：the; /
答案(点此获取答案解析）
D
My sister likes playing_____guitar and she also likes playing______soccer.
A：the; the
B：/; /
C：/; the
D：the; /
。为使弹簧振子的振幅最大,则电动机的转速应为( )