单项选择题
A．on B．in C．off D．onto
A．Eating and Sleeping in Space B．How Astronauts Eat in Space C．Food for Space D．How Astronauts Sleep in Space
A．He knows where to place the needles without pain. B．He knows where the operation is to be performed. C．He knows how to perform the operation to cure the patient. D．He knows how to use the needles in an operation.