问题补充：
they were not rich, they tried their best to send their child to the best school.
A. However
B. Because
C. Even though
D. So
答案：
A. However
B. Because
(答案→)C. Even though
D. So
解析：考查连词：A. However无论怎样B. Because因为C. Even though即使D. So因此，语境，虽然他们不富裕，但还是尽量把孩子送到最好的学校。故选C
