问题补充：
Only the painting decide whether it is worth buying.
A. that he sees; can he
B. that does he see; he can
C. when he sees; can he
D. when does he see; can he
答案：
A. that he sees; can he
B. that does he see; he can
(答案→)C. when he sees; can he
D. when does he see; can he
解析：考查only的倒装句：only+状语（介词短语，副词，状语从句）后面的主句要部分倒装，这句话only+when引导的时间状语从句，（从句不倒装），后面的主句倒装，can提到主语前面，句意：只有当他看见这幅画的时候，他才决定这幅画是否值得买。选C。
