Karipidis
said that having more cellphone towers actually reduces the amount of radiation
emitted from cellphones, because they don't have to work as hard to get a signal.
they don't have to work as hard to get a signal. they 是主语, don't have to work 看作谓语,have to 可以看作半助动词。as hard =equally hard,指和过去比,相当于as hard as before. 此句中as相当于equally. as hard 看作程度状语。