从A、B、C、D 四个选项中，选出可以填入空白处的最佳选项
21. Don’t worry too much about making ____ mistakes. They are _____ natural part of learning.
A. /; a B. the; / C. /; the D. the; the
22. Tom was very sick with a bad cough. ______, he could neither eat nor sleep.
A. As a result B. After all C. Anyway D. Otherwise
23. Two thirds of the work ____ done by Jimmy, and ___ was done by Nancy.
A. was; the rest B. was; the others C. were; the others D. were; the rest
