【評論主題】22 Since Richard attended college, he _________ his living by doing all kinds of part-time jobs.(A)

【評論內容】Since.....,S Have/has+ p.p

【評論主題】20. The social welfare system ____________ provide the underprivileged people with sufficient suppor

【評論內容】due to=because of,as a result of,owing to,thanks to

【評論主題】22 Since Richard attended college, he _________ his living by doing all kinds of part-time jobs.(A)

【評論內容】Since.....,S Have/has+ p.p