[Alex80]

Hi everyone!
Can we make the answers to these questions shorter ?
1.How could the police avoid mistakes when using radar guns?
The police could avoid mistakes if the radar guns are used correctly and police officers are trained to use them properly.
Is it correct to say:
-If the radar guns are used correctly and police officers are trained to use them properly.(omitting the main clause) if that's correct, can we make the sentence more shorter? What changes are needed to start the answer with 'By' ?

2.what does the whole section of books about different careers in a library describe?
-It describes the various jobs and tells what skills or qualifications we need to do them. (Can we make the answer shorter by omitting 'it describes' but leavingthe verb 'tells'
Thanks in advance