【正确答案】 C

【答案解析】occasionally与sometimes意思相近：有时；偶尔。I drink coffee only occasionally．我只是偶尔才喝咖啡。regularly：定期地，有规律地。The doctor told him to check his blood pressure regularly．大夫要他定期地查血压。accidentally：意外地；偶然地。I accidentally found the book I had been looking for．我偶然找到我一直在找的书。successfully：成功地。 We have completed the experiment successfully．我们成功地做完了实验。