问题补充:
Kates dad is getting old. She will go back home to see him it is convenient.
A. because
B. whenever
C. although
D. unless
答案:
A. because
(答案→)B. whenever
C. although
D. unless
解析:because因为;whenever每当,无论什么时候; although虽然,尽管;unless除非,如果不。句意:凯特的父亲老了。每当她方便的时候,她就会回家看他。结合语境可知选B。