At 13，Samuel received a training course in drawing for three years， he got a good opportunity for further development.
A. after that
B. after which
C. after it
D. after this
网友回答
A. after that
B. after which
C. after it
D. after this
解析： B
解析 after which意为“after he received a training course in drawing for three years”。句中没有并列连词，故不能选C、D两项；that不能引导非限制性定语从句，故A错。