1.While—When或After.本句的this指代的是to change the weather by using magic. when/after 引导时间状语
2.in—than.earlier是early的比较级，其后应有than
3.those之后加who.who引导定语从句
4. 删除advance前的the.in advance为习语
5. take—have.have connection with 为习语
6. controlled—controlling或在controlled前加that/which.controlling the weather 或that/which controlled the weather做定语修饰the actual factors
7. and—or.rain和draught只能是二者之一
8. 删除is.与上文平衡，均为省略句
9. before—when/if.条件句
10. will—would.if引导的是条件句用的是remained一般过去时