时态改错.
Bytheendofthesummerwe'llhavebeenvisiting17countries.
ByJulywe'llhavebeentraveledfortheremonths.
We'llpickherupat8:00Am.ifthetrainwillarrivebythen.
Callmewhenyougetbacktothehome.PerhapsI'mgoingtobeup.