Thecontrolsofmostmodernairplanescanbeoperatedeithermanuallyorautomatically.
A、bythebookBats fly, rather than glide, and thus are the only mammals capable of true flight.
Anoversight遺漏(miss,overslaugh)inproofreadingoftenresultsinprintederrors.
When carbon is added to iron in the proper proportions , the result is steel.
Someanimalspantandsweattospeedevaporationofbodymoistureandthuscoolthemselves.
In 1974 Henry Aaron broke Babe Ruth's monumental lifetime record of 714 home runs.
