21-by-100-foot space,是个常用语吗?

21-by-100-foot space,是个常用语吗? foot by a space six by ten I _____to space by rocket. 31inches by 7 foot 翻译two-by-two-foot By foot 和 on bike 为什么英语步行是on foot而不是by foot? I miss you by a space developed by the chinese space agency . MsBrown goes to walk by foot.改错 I usually come home by bike,but sometimes I come( )A.by foot B.by the foot C.on foot D.on the foot I often go ?.?处是填by foot,by walk,on feet还是on foot? she go to school by foot.a go.b school...can by.d foot.改错 step by step,foot by foot这两者的区别是什么? space space 1.China has set foot ___ space.A.in B.on