Which of the following is true about sentences that are grammatically complex

In order for a sentence to be grammatically correct, the subject and verb must both be singular or plural. In other words, the subject and verb must agree with one another in their tense. If the subject is in plural form, the verb should also be in plur al form (and vice versa). To ensure subject-verb agreement, identify the main subject and verb in the sentence, then check to see if they are both plural or singular. Consider the examples below.

Incorrect examples - Subject-Verb Agreement

"The group of students are complaining about grades."
The main subject in this sentence is "group," which is singular. The main verb is "are complaining," which is plural.

"A recipe with more than six ingredients are too complicated."
The main subject in this sentence is "recipe," which is singular. The main verb is "are," which is plural.

"The facts in that complex case is questionable."
The main subject in this sentence is "facts," which is plural. The main verb, "is," is singular.

"The people is wearing formal attire."
The main subject in this sentence is "people," which is plural. The main verb is "is wearing," which is singular.

Correct examples

"The group of students is complaining about grades."
"A recipe with more than six ingredients is too complicated."
"The facts in that complex case are questionable."
"The people are wearing formal attire."

A variation of the subject-verb agreement is pronoun-reference agreement. In the case of pronoun-reference agreement, all of the pronouns should agree with one another in singular or plural tense. Consider the examples below.

Incorrect examples - Pronoun-Reference Agreement

"A manager should always be honest with their employees."
The subject in this sentence, "manager," is singular. The corresponding pronoun, "their," is plural.

"Organizations must be careful about discriminating against its employees."

The subject in this sentence is "organizations," which is plural. The corresponding pronoun, "its," is singular.

"If you really care about somebody, let them make their own choices."
In this sentence, the pronoun "somebody" is singular, but the corresponding pronouns, "them" and "their" are plural.

Correct examples

"A manager should always be honest with his (or her) employees."
"Organizations must be careful about discriminating against their employees."
"If you really care about somebody, let him (or her) make his (or her) own choices."

Parallel Structure

The parallel structure of a sentence refers to the extent to which different parts of the sentence match each other in form. When more than one phrase or description is used in a sentence, those phrases or descriptions should be consistent with one an other in their form and wording. Parallel structure is important because it enhances the ease with which the reader can follow the writer's idea. Consider the following examples.

Once you can identify a basic sentence, you can join two or more sentences into complex sentences.  Two or more sentences can be combined with a subordinating conjunction that explains the relationship between each idea.

For example:

Simple Sentences - He studied hard. He wanted to go to medical school. He suffered from arthritis.

Complex Sentence - He studied hard because he wanted to go to medical school as he suffered from arthritis.

Complex Sentence - Even though he suffered from arthritis, he studied hard because he wanted to go to medical school.

Notice how the subordinating conjunction adds additional meaning to the sentence. The last two sentences tell us why he studied.

Some Common Subordinating Conjunctions:

After

Before

So that

Whenever

Although

Even though

Though

Where

As

If

Unless

Whereas

As if

In order that

Until

Whether

Because

Since

When

while

A subordinating conjunction is sometimes called "a heart word" because it turns two sentences into one. Even though both sentences contain a subject and verb, one becomes dependent on the other and cannot stand alone. One sentence becomes the explaining idea for the main idea.

Any time you see words like the ones above, check that your sentence doesn't leave a question remaining.

 For example:

Wrong - When he came late to class. (What happened when he was late?)

Right - He forgot to give the teacher his homework when he came late to class.

Wrong - After she noticed it missing. (What happened when she noticed?)

Right - The teacher asked for his homework after she noticed it missing.

Wrong - Because they knew the test would be difficult. (What happened as a result?)

Right - The students studied furiously because they knew the test would be difficult.

Punctuation depends on the location of the subordinating conjunction:

If the subordinating conjunction comes at the beginning of the sentence – add a comma at the end of the dependent clause.