TOEFL Sample essay : integrated essay from TPO9

The lecturer points out several problems with the use of hydrogen-based fuel-cell engines in support of her claim that substituting them for internal-combustion engines is technologically unfeasible, environmentally unfriendly, and economically unviable.

First, the lecturer states that it is impractical to replace internal-combustion engines with fuel-cell engines because using the latter requires hydrogen in a pure liquid form, which is technologically challenging to both obtain and store. However, the reading argues that because hydrogen can be extracted from many resources including wate...