Parrots have been known to mimic words, but have you ever thought how they communicate? The sounds ...

查看本题答案

包含此试题的试卷

is not known are not known has not known have not been

knowing to be known having known known

knowing to be known having known known

will be knowing will have known have known have been knowing

It As That What

knowing to be known having known known

has not known are not known has not been known have not been known

intending; have been made known intended; have been made known intending; are made known intended; had made known

knew had known have known have been knowr

intending; have been made to know intended; have been made known intended; have been made to be known intending; have made to be known

isn’t known aren’t known has not known have not been known

have washed; have known have been washing; knew have washed; know have been washing; know

know have known knew have been known

have been known to scientists for many years have only recently been discovered are known by us will probably remain a mystery

having been going on go on have been going on be going on

did I know I knew have I known I have known

intending; have been made known intended; have been made known intending; are made known intended; had made known

had known, would not be had known; wouldn’t have been knew; would not have been had known; would never be

being having been to be to have been