英和和英

under investigation

inquire into

make a survey of

do research

I'm researching

inquiry into one's birth and parentage―inquiry into one's antecedents

to make a close investigation―a minute investigation

actual investigation―personal investigation

make a survey of public opinion

a narrow examination

As a result of inspection...

do a survey

exact investigation

within the scope of an investigation

census-taking

a review of the literature

matters requiring investigation―matters for investigation

a thorough investigation

study in the field

a house‐to‐house survey

a policeman on patrol

exploratory reconnaissance

close investigation

a comprehensive survey

prosecute an inquiry

under examination

a full-dress investigation

hold an official inquiry

to take the census

by inquiry