1. ______, it is quite easy to drill a hole in it with a laser. A. Hard a diamond is B. Hard as a diamond is C. As a diamond is hard D. How hard is a diamond
2. We hope that both sides exert calmness and ______ and continue to dissolve differences through negotiation. A. constraint B. restraint C. limitation D. restriction
【考博英语补全句子】 _________ _________（首先）, we should pay more attention to the importance of wildlife protection.
