10.on替换as soon as

　　As soon as he arrived, he began his research.

　　On his arrival, he began his research.

　　11.due to替换because of

　　He arrived late due to (because of) the storm.

　　12.cover替换walk/read

　　After covering (walking) 10 miles, we all felt tired.

　　13.contribute to替换be helpful/useful

　　Plenty of memory work is undoubtedly helpful to English study.

　　Plenty of memory work will undoubtedly contribute to English study.

　　14.round the corner 替换 coming soon/ nearby

　　① The summer vacation is round the corner ( coming). Do you have any plans?

　　② Li Ming studies in a school round the corner (nearby).

　　15.come to light替换discover

　　The family were so pleased when they discovered the lost jewels. →

　　The family were so pleased when the lost jewels came to light.

　　16.have a ball替换have a good time/ enjoy oneself

　　After visiting the workshop, we went back to school. Every one of us had a ball (hada good time).

　　17.come up with替换think of

　　Jack is very clever. He often comes up with (thinks of) new ideas.

　　18.set aside替换save

　　Some students think that they should set aside some of their pocket money for books.