春秋时期的第一个霸主是_________，决定晋文公成为中原霸主的战争是___________。
齐桓公；城濮之战
解关于x的方程：kx+m=（2k-1）x+4．
The girl was nervous in front of so many strangers and we did all we could to make her feel more ____. [ ]
A. at ease
B. in silence
C. for fun
D. with joy
