Some of the experiments ______ in the book are easy to perform.
A. being described B. described C. to be described D. having been described
出自:统招专升本-----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