Meyer and his team were the first ______ how the disease spreads from animals to humans.
A:showing
B:show
C:to show
D:shown
取含有草履虫的池塘水于烧杯中,不久就会发现草履虫都集中在水的上层,原因是草履虫需要( )
你想问同学在家会做什么时,你应该说:_________