D - he faills to emphasize words to highlight his main point
She <span>had been working</span> on the project for 2 days before she finished it. So B is the only right one as it's a continuous action before an action with an exact defining past perfect continuous. Also there's a key word "for" that can help us to find out the tense.
<u>Here are some of the advantages and disadvantages of watching television:</u>
Pro: Free entertainment. ...
Pro: Social surrogacy. ...
Pro: Educational channels. ...
Pro: Family bonding. ...
Con: Television can make you lazy. ...
Con: Violence & illicit content. ...
Con: Consumerism. ...
Con: Health Hazards.
