The question set by the teacher was so difficult that the students did not know how to tackle it.
出自:河南城建学院英语(二)(专升本)

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