问题补充：
Homework , I turned on the computer and tried to do some online shopping.
A. finishing
B. finished
C. to finish
D. finishes
答案：
A. finishing
(答案→)B. finished
C. to finish
D. finishes
解析：句意：作业完成了，我打开电脑想在网上购物。这里两句话之间没有连词，说明前面的不是句子，而是独立主格结构做状语，由“逻辑主语+非谓语”构成，因为Homework和finish是被动和完成的关系，用过去分词，选B。
