问题补充：
The large family is really a heavy on his shoulder, so he has to work day and night.
A. job
B. challenge
C. load
D. weight
答案：
A. job
B. challenge
(答案→)C. load
D. weight
解析：A. job工作 B. challenge挑战 C. load负担 D. weight重量；句意：这个大家庭对他来说是个大的负担压在他的肩膀上，所以他不得不夜以继日的工作。故选C
