单项选择题—When was the first man with A(H1N1) flu in mainland China known for sure —______ May 11, 2009.
单项选择题One of the boys is ______, all the other boys are ______.
单项选择题The head of the executive branch in New Zealand is______.
单项选择题It is reported that the police will soon ______ the case of two missing children.
单项选择题() Yellow River is the second longest river in our country.
A. / B. The C. An D. A