问题补充：
It is to improve the working conditions for the construction workers.
A. worthwhile
B. worth
C. worthy
D. worthy of
答案：
(答案→)A. worthwhile
B. worth
C. worthy
D. worthy of
解析：句型辨析。 Worthwhile (adj) 值得的worthwhile用于下列句型It is worthwhile doing sth./ to do sth.干某事是值得的worth用于下列句型：sth. is worth sth/ doing此句型中只能用doing， 不能使用被动。 worthy用于下列句型：sth. be worthy of sth/ being done sth. be worthy to be done。故选A。
