成人股骨头的血供主要来自
A．股骨头圆韧带的小凹动脉
B．股骨干滋养动脉
C．骺外侧动脉
D．干骺端上、下侧动脉
E．旋股内外侧动脉
Hold your dream,_________ you might regret some day.
A. and
B. or
C. but
D. so
He can't bear ________ she said to him yesterday.
A. when
B. what
C. where
D. which
—Can Frank come to your birthday party?—I'm not sure ________ he can come here or not, because he's busy
A. until
B. that
C. whether
D. when
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