问题
选择题
The children were playing games on the playground, ________ school uniforms.
A．all of them wore
B．all wearing
C．all of whom wearing
D．all were wearing
答案
答案：B
句子中没有连词，所以排除A,D；而C选项不是完整的定语从句，所以选B，用动词的ing形式。