B is wrong because it does not necessarily refers to energy only, but refers to more than ten times as much energy...now , how can we say the energy generated...now is as much as it(the energy generated...now) was in 1990 ? I recalled one question that is similar to this one just for reference. Ove...

great example ron.. if in your above example, i write the air quality of las vegas was higher in 2007 than that was in 1997...is it parallel? if it is not, please give an example how to make this example parallel actually, there is no way to make this example work -- you cannot use "that" as a pro...

It looks like there are some typos in the original: who do not respond TO therapies FOR depression? In any case, the verb tenses are inconsistent in E: "for example, when they have a drug prescription with a dosage too low to be effective, or been" To shorten it: "...when they have X...

The OA is D. Is "sighted plusar" better than "to be sighted", since the pulsar has alreadly been sighted? no, 'to be sighted' is better for at least two reasons. (1) 'first NOUN to be VERBed' is generally the preferred form in discussing the results of human efforts/actions/inte...