These Aching Calf Muscles Causes Are Hidden In Your Daily Footwear
"those / these" are determiners and are used before nouns to refer to a particular group of things / people, e.g. these people / those rules / those buildings. Update: 题主问的是What are those? 然后他.
Aching Bad Calf Cramps: Causes, Treatment, Prevention » Scary Symptoms
