<p>for number 21 :
The new system, which USES (A) remote cameras IN THE CATCHING OF (B) SPEEDING MOTORISTS ( C), MAY UNDERMINE (D) the police department's authority. no error (e)</p>
<p>why is it B? too wordy?</p>
<p>you dont say "in the catching of", it just sounds wrong</p>
<p>it should be "to catch speeding motorists" instead</p>