The Blacks ___ in this factory since 1998 A has worked B has

The Blacks ___ in this factory since 1998 A has worked B has Mr Green has worked in this factory since 1998. Mr Smith has worked in this factory since he ( )to China A.h He;s worked in this factory for many years ------ he?A.has B tom has been in the factory --- he left school.a.since b.as My mother has worked in this factory 2 years. Mr.Brown has worked in the factory __________15 years.A.for Has Mr LI worked in this factory for 35 years?--Yes,he has.I he has been away from the factory .a a week ago b since a we He said he ( ) in that factroy since 1949.A.has worked B.had My father has worked in this factory ____ we moved to this c His father has worked in this factory _____ he came here in