Exercise Twenty-One
1. We had better _________________（天天锻炼身体）.
2. _______________（为了不影响他们），we left quietly.
3. _____________（我答复她）that I would accept her invitation.
4. According to the newly-announced policy，we should ________________（努力搞活国有大中型企业）.
5. It has become an utmost urgency that ________________（必须清除政府中的贪污腐化现象）.