简述系统计算的主要内容。
参考答案:
系统静平衡的计算;系统曳引能力的计算;驱动器功率的计算;作用在安全钳上载荷的计算;底坑反力的计算,顶层高,地坑深的计算。
根据我国《禁毒法》之规定,目前我国的禁毒模式共有自愿戒毒、社区戒毒、强制隔离戒毒三种。()
Two farmers were on their way home one evening after a hard day’s work. Both were tired. They happened to look up at the sky and saw a black cloud overhead. "Ah!" said one farmer, "tomorrow we shall have rain and the rice will grow well." The second answered, "Nonsense, the rain will only kill the crops." So they began to quarrel. Just then a third farmer came along and asked them why they were quarreling. Both farmers explained about the black cloud. "What cloud" asked the third farmer. They all looked at the sky. The cloud was no longer there.
The two farmers fought in words because ______.
A.they were hungry
B.it rained
C.one said the rain would do good to the crops and the other didn’t think so
D.they both hoped for rain