Q.1.
One deer but many .......
Q.2.
One fish swimming in the river but seven .......
Q.3.
One species of animal but thousands of .......
Q.4.
An army barracks (accommodation), or multiple .......
Q.5.
A herd of swine (i.e. pigs) but one .......
Q.6.
One headquarters but nine .......
Q.7.
One red-nosed reindeer but six .......
Q.8.
One sheep but two .......
Q.9.
One cod but a shoal of .......
Q.10.
One series of "Dr. Who" but three .......