A:(What's )this（ in）English?
B:（It's ）a jacket.
A:( Spell )it please.
B:J-A-C-K-E-T
A:Waht （colour ）is it?
B:（ It's ）yellow
A:Thanks( a ) ( lot ).
B:You ( are ) ( welcome ).为什么是A:Thanks( a ) ( lot ).B:You ( are ) ( welcome )这是英语的基本客套话。多谢你了。别客气。