Dinosaur scientists can probably know whether dinosaurs were good parents by __________ .

• A、watching many kinds of animals 

• B、studying dinosaurs' living relatives

• C、following the tracks left behind

• D、working on dug-out dinosaur eggs

--Have you been paid for the painting?--Yes, I remember__________$ 60 for it.

• A、to have paid

• B、to pay

• C、being paid

• D、paying

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