David had to __________the invitation to the party last weekend because he wasn't free（ ）
A．turn onB．turn downC．turn upD．turn off
The volunteers ________ a lot of help to the old and the young since 2010．（ ）
A．offeredB．have offered
C．are offeringD．will offer
Of all the drinks，tea is ________ in the world．It has a history of about 5，000 years．（ ）
A．oldB．olderC．the oldestD．very old
For our safety，we must ________ the traffic rules on the way to school．（ ）
A．followB．changeC．makeD．break
Reading is a good way to spend the time on the plane．
That's true．I never go travelling ________ a book．（ ）
A．withoutB．fromC．onD．about
Everyone makes mistakes in life．The key is not to repeat ________ again．（ ）
A．itB．thisC．thatD．them