My car’s performance is ___ since the engine’s been tuned and the tires have been changed．

 I haven’t seen______ this since I collected stamps.

 All the things _________ must be done well．

The washing machine is environmentally friendly because it uses ___ water and electricity than ___ models.

The first African-American president of the United States received a（n） _____ welcome in the African countries, where he was received as a returning son．