One theory, ________ suggested by Harvard University, is that humans began cooking their food, thereby releasing nutrients locked in the raw food and reducing the time needed to chew it.
A．which B．as
C．that D．what
________ is shown in the report, teenager problems are often connected with family life education.
A．Which B．As
C．It D．What
They told me they had just arrived at the last destination ________ you went to last year.
A．where B．that
C．when D．which
．Soon children in the camp had many new friends, ________ they shared food, stories, and projects.
A．for which B．with whom
C．of which D．to whom
________ is often the case with human beings, many animals sleep a lot when young, but sleep much less when they get older.
A．Which B．What
C．As D．That
Jennifer is always absent from school, ________ I suppose is why she is blamed now and then.
A．which B．who
C．that D．what
