Question

n December 1937, the Japanese forces invaded______ and carried out destructive military operations over a period of _______
Blank 1
Shanghai
Nanjing
Beijing
Blank 2 
Three months 
Seven days
Six weeks

Answer 1

In December 1937, the Japanese forces invaded Nanking and carried out destructive military operations over a period of 6 weeks

Answer 2

In December 1937, the Japanese forces invaded "Nanjing" and carried out destructive military operations over a period of "six weeks." 

I hope this helps you.