乳牙建完成时下颌角为()
A.100°~120°
B.120°~125°
C.130°~140°
D.140°~160°
E.150°~170°
参考答案:C
汽车刹车后做匀减速直线运动,经过3s就停止运动,那么,在这连续的三个1s内,汽车通过的位移之比为
A.1:3:5
B.5:3:1
C.1:2:3
D.3:2:1
A chart projection depicting the poles and a small area on either side of a connecting meridian,that is sometimes used for star charts,is the().
A.azimuthal gnomonic projection
B.Lambert conformal projection
C.transverse Mercator projection
D.polyconic projection