一个半圆，半径是R，它的周长是（ ）。
πR+2R
根据问句写出答语。
l.-What are the men doing?
-______ ______ playing football.
2.-What is the boy doing?
-_____ _____ sleeping,
3.-What are the children doing?
-_____ _____ crying.
腰椎结核临床常见的体征是
A．Thomas征阳性
B．“4”字试验阳性
C．拾物试验阳性
D．直腿抬高试验阳性
