支气管肺癌的早期表现为（） A.刺激性咳嗽持续2～3周，治疗无效 B.新近出现持续性

HMIWEB Display Builder中，（）意思为选择对象置为最前。

村镇居民点用地选择的卫生要求叙述中哪一项是错误的（）

A.避免选取在地方病高发区和自然疫源地区

B.地势高，干燥，地下水位要低

C.土壤要清洁，要有良好水源

D.背风向阳，最好向东南倾斜有一定坡度

E.交通方便，为便于村民往来穿境交通最好经过镇中心

Routing protocols use different techniques for assigning ______ to individual networks. Further, each routing protocol forms a metric aggregation in a different way. Most routing protocols can use multiple paths if the paths have an equal ______ . Some routing protocols can even use multiple paths when paths have an unequal cost. In either case, load ______ can improve overall allocation of network bandwidth. When multiple paths are used, there are several ways to distribute the packets. The two most common mechanisms are per-packet load balancing and per-destination load balancing. Per-packet load balancing distributes the ______ across the possible routes in a manner proportional to the route metrics. Per-destination load balancing distributes packets across the possible routes based on ______.

A. bandwidthsB. sources C. destinations D. delays

等离子束发生器进行切割时使用的是（）作为产生离子体的介质。

A.酒精

B.蒸馏水

C.水

D.丙醇

下列说法中正确的是（）

A.物体的动量改变，一定是速度大小改变

B.物体的动量改变，一定是速度方向改变

C.物体的运动状态改变，其动量一定改变

D.物体的速度方向改变，其动量一定改变