23．By the end of this term, we___________ 3,000 English words in all.
A will learn B. will have learned C. have learned D. had learned

[B] 本题主要考查将来完成时，根据句意：到这个学期结束时，我们已经总共学习了3000个英语单词。可知是说明将来的情况，故用将来完成时，应该选B。A选项是将来时，C选项是现在完成时，同样地，如果改成by the end of last term,本题就选D项，表示截止到过去某个时间点，产生的影响和结果。