You may imagine what great difficulty I had complicated ideas in simple English.A. expres

问题补充：

You may imagine what great difficulty I had complicated ideas in simple English.

A. expressing

B. to express

C. expressed

D. express

答案：

(答案→)A. expressing

B. to express

C. expressed

D. express

解析：句意：你可以想象我用简单的英语表达这里复杂的想法是多么困难。这里使用了词组：have difficulty （in） doing做…有困难。这里省略了介词in，所以后面接动名词，选A。