The squall line is a kind of instable and strong convective weather caused by the air with upper-layer dry and lower-layer wet in front of the upper-troposphere trough.
分析指出，该飑线系统是由高空槽前型的上干下湿引起的不稳定强对流天气。
2
Stay seated; utilize a combination of the forks rebound, upper body strength and power on the cranks to loft the front of your bike in the air.
坐在车座上，把上身的力量集中在横把上，利用叉子回弹的合力使前轮离地。
3
The major systems come from the shear line of low-layer, the low trough of upperair and the ground stationary front.