The teacher told the children that the sun _____ round.        [ ]

A. was      

B. is      

C. were      

D. are

重症肌无力一般哪组肌肉不受累（）

A.膀胱括约肌

B.咀嚼肌

C.颈肌

D.呼吸肌

E.平滑肌