The kids are kept( ) tidying up the desk. A. busy with B. busying with C. busy in D. to busy in
出自:国家开放大学开放英语

完成拼图验证

按住下方滑块,将拼图拖到缺口处后松开。

拼图背景,将小拼图拖到缺口处
向右拖动滑块