173. We’ve decided to leave early tomorrow morning. (SET)

=172. We have an emergency electricity supply in case we are cut
off. (BACK)

171. Interrupting when someone is speaking is rude. (CUT)

170. The numbers of cars on the roads must be reduced. (DOWN)
 

169. Despite his ungainly air he is remarkably agile.
→Although 

168. The chances are that the whole thing will have been forgotten
by next term.
→In all 

167. The students’ riotous behaviour should have been severely
punished.
→The students deserved

166. I don’t know the first thing about aeronautics.
→I am 

165. The Prime Minister was determined to remain in office.
→The Prime Minister had 

164. Most people regard Dr. Peters as being the best surgeon in his
field. (WIDELY)