23. None of the underwater workers has been harmed by the great fish. ______, most fish were so friendly that they played with the instruments.
A
Instead
B
Even though
C
However
D
Though
instead 表转折和对比；故选项A正确。
前半句提到“大多数水下工作人员并没有瘦到鱼的伤害”，相反，很多鱼非常友好。前后句是对比的关系。
对句子前后关系把握不准致错。