On video， Doctor Zhong Nanshan ________ teenagers to study hard in the first lesson of this term．（ ）
A．allowedB．trainedC．encouraged
﹣The water in the glass is sweet．Did you put any in it？（ ）
﹣Yes．I added some to it just now．
A．sugarB．saltC．oil
﹣Is that apple tree？（ ）
﹣Yes．My father planted it in 2008．
A．aB．anC．the
﹣Excuse me，could you tell me ______ in Puxian Theater？（ ）
﹣For ten minutes．
A．how soon will the concert begin
B．how long has the concert been on
C．how long the concert has been on
Susan's mother looks so young．It's hard to imagine she's already in her ______．（
A．sixtyB．sixtiesC．sixtieth
With the development of modern technology，we prefer taking photos with ______ instead of camera．（ ）
A．
B．
C．