如图所示,要想在光屏上出现缩小的像,应该把点燃的蜡烛放在( )
A:“A处”
B:“B处”
C:“C处”
D:“D处”
下列各项中,属于血液传染病的一组是( )
造成我国南方与北方耕地类型差异的主要自然因素是( )
It was only after he had read the papers ________ Mr. Gross realized the task before him was extremely difficult to complete.