adj.
VERBS
▪ appear , be , look , seem , sound
▪ become
▪ make sth
ADVERB
▪ extremely , fairly , very , etc.
▪ highly , incredibly , remarkably
▪ perfectly
▪
We already have a perfectly ~ system—why change it?
▪ brutally , ruthlessly
▪
He was ruthlessly ~ in acquiring estates.
▪ increasingly
▪ reasonably , relatively
▪ economically , environmentally , technically
PREPOSITION
▪ at
▪
Their equipment was not as ~ at finding gold as today's machinery.
▪ in
▪
The heating system is very ~ in its use of of fuel.
Efficient is used with these nouns: ↑ administration , ↑ allocation , ↑ collection , ↑ delivery , ↑ deployment , ↑ exploitation , ↑ machine , ↑ management , ↑ manner , ↑ means , ↑ method , ↑ operation , ↑ organization , ↑ producer , ↑ production , ↑ running , ↑ service , ↑ system , ↑ technology , ↑ transfer , ↑ transport , ↑ transportation , ↑ use , ↑ way