Artemisinin _______ by Tu Youyou,a great Chinese scientist.( )
A.was inventedB.invented
C.has invented
--I can’t solve the math problem because it is too difficult. What should I do?-- _________ ask the teacher for help?
— ? —I like action movies.
—— do you of the sports shows? ——They’re interesting.
What colour sweater do you like ,green ______ blue?
— does Jim to school? —By bus.