吊车应用了许多物理知识，如轮胎上有很多花纹，是为了_____;吊起货物过程中，支撑臂和起重臂共同构成一个_____(选填“省力”或“费力”)杠杆;吊车在行驶过程中驾驶员要系好安全带，主要是为了防止_____带来的危害;用水作为发动机的冷却液，是因为水具有较大的_____.
在压力一定时，通过增大接触面的粗糙程度来增大摩擦力、费力、惯性、比热容
-----Didyounoticehimcomein?
-----No.I________afootballgame.
Advertisingdiscouragespeoplefrombeingdifferentindividualsbymakingusallwanttodothesameandlookthesame.Doyouagreeordisagree?
Theyalsorecognizethatstresscanresultinstress-relatedillnesses,suchashighbloodpressure,ulcers,andfatigue.
Thereisamixtureofpeoplefromdifferentculturesandethnicgroupsinacountry.Why?Isthisapositiveornegativedevelopment?