subject, voice, or mode in the middle of
a sentence. Keep one point of view, until there is a reason for
changing.=

Faulty: In the stream which the road led over, fish were
plentiful. [Here the first mental picture is of a stream. Then
the thought is jerked away to the road above. Then it returns
to the fish in the stream.]

Right: In the stream which flowed under the roadway, fish were
plentiful.

Faulty: Mark Twain was born in the West, but the East was his
home in later years. [The change of subject is uncalled for.]

Right: Mark Twain was born in the West, but lived in the East
in his later years. [Or] The West was the birthplace of Mark
Twain, and the East was his home in his later years.

Faulty: A careful driver can go fifteen miles on a gallon of
gasoline, and at the same time very little lubricating oil is
used. [The shift from active to passive voice is awkward and
confusing.]

Right: A careful driver can go fifteen miles on a gallon of
gasoline, and at the same time use very little lubricating oil.

Faulty: When a problem in chemistry is given, or when we wish
to calculate certain formulas, we find that a knowledge of
mathematics is indispensable.

Right: When a problem in chemistry is given, or when certain
formulas are to be calculated, a knowledge of mathematics is
indispensable. [Or] When we face a problem in chemistry, or
wish to calculate certain formulas, we find that a knowledge of
mathematics is indispensable.

Faulty: Next the ground should be harrowed. Then you sow the
wheat. [The subject changes from _ground_ to _you_. One verb
explains what _should_ be done, the other what somebody
_does_.]

{is }
Right: Next the ground { } harrowed. Then it
{should be}
{is }
{ } sown to wheat. [Or] Next you should harrow
{should be}
the ground. Then you should sow the wheat.

Exercise:

1. One end of a camera carries the film, and the lens and
shutter are in the other end.

2. When an athlete is in training, good healthful food should
be eaten.

3. An engineer's time is not devoted to one branch of science,
but should include many.

4. By having only five men in charge of our city government,