如图为悬挂街灯的支架示意图,横梁BE质量为6kg,重心在其中点。直角杆ADC重力不计,两端用铰链连接。已知BE=3m,BC=2m,∠ACB=30°,横梁E处悬挂灯的质量为2kg,则直角杆对横梁的力矩为 N·m,直角杆对横梁的作用力大小为_______N。
On weekends, many people like taking food and tents to go (露营)in the mountain.
We need two (小刀)to cut up the bananas to make a banana milk shake.
"Could you please tell me where the bookshop is?" the boy asked (礼貌地).
Please turn to Page 10 and look at the (第八)picture on it. Let's talk about it.
The government will (建造)a bridge across the river next year.