一道英语选择题:Sincehewasoutofjobfromthecomputercompany,Joseph----
全文:Sincehewasoutofjobfromthecomputercompany,Joseph----goingbacktoschool,buthehasn’tdecidedyet.
A.hadconsidered
B.hasbeenconsidering
C.considered
D.isgoingtoconsider
并请解释一下选择的理由