马拉着质量是2000千克的车,在平路上前进了400米,做了3×105焦的功,则马的水平拉力是___________牛.
750
甲亢病人浸润性突眼下列描述中哪项不妥()
A.眼内异物感
B.视物模糊或复视
C.流泪
D.易致角膜炎或角膜溃疡
E.突眼程度往往双侧对称
Mr Zhang isn't here. He's flown to Tibet, ______? [ ]
A. ha she
B. hasn't he
C. is he
D. isn't he