题干
Over fifty countries _______ the AIIB(亚投行) so far.
A：joined
B：was joining
C：had joined
D：have joined
答案(点此获取答案解析）
D
Over fifty countries _______ the AIIB(亚投行) so far.
A：joined
B：was joining
C：had joined
D：have joined
B（g），在相同条件下，若分别再向容器中通入一定量的A气体或者B气体，重新达到平衡后，容器内A的体积分数比原平衡时 （ ）
