When I entered the room, I found a little boy _____ on his mother’s knees _____ to draw a picture.

A．seated; learning

B．sitting; to learn

C．seating; learning

D．sat; was learning

人类 * * 瘤样病毒对胎、婴儿的主要影响是（）

A.早产

B.宫内感染

C.婴儿喉 * * 瘤

D.胎儿宫内生长受限

E.婴儿期后发生恶性肿瘤