用淀粉为原料制取酒精，若有1 kg含40%淀粉的植物果实，经过反应制得227 g 80%的酒精．淀粉的转化率为________．

So engrossed in his efforts would Gaugin become that he barely noticed the passing of time.

A．delighted in

B．frustrated by

C．expanded by

D．involved in