Constructed at least as early as the Sui dynasty (A.D. 581-618), the A

Let's start with some quick definitions. A fragment is a piece of a sentence that lacks either a subject or a verb. For example:

Tim, who is a person of interest in at least 17 investigations involving juice box embezzlement.

Here we have a subject, Tim, and a "who" modifier describing Tim. Because there is no main verb connected to the subject, it's a sentence fragment, and therefore incorrect.

A run-on sentence is one in which two independent clauses lack a proper connector, such as a conjunction or a semi-colon. For instance:

Tim has been indicted on serious juice-box charges, he hopes to mount a vigorous defense by enlisting his five-year-old daughter as legal counsel.

Notice that both the portion in red and the portion in blue are independent clauses - each can stand on its own as a complete sentence. We could connect those clauses with a conjunction, such as "and." We could also connect them with a semi-colon. But we cannot connect them with a comma alone, so this sentence is incorrect.

Now to our answer choices:


Here we have the exact same problem as the previous sample sentence. The portion in red and the portion in blue are both independent clauses. Because they're connected with only a comma, we have a run-on. (A) is out.


This one looks okay. The Altar of Heaven has two attributes: it is more than 100 years old and is the only alter that predates the Qing dynasty. This time we get rid of the second subject and we have an "and" connecting the two verbs. Nothing else seems problematic, so hang on to it.


That modifier in red creates a confusing meaning: Is it saying that The Altar of Heaven was constructed as early as the Sui dynasty and was also constructed as early as the oldest known altar, presumably some other altar? Or is it saying that The Altar of Heaven was constructed as early as the Sui dynasty and that the Altar of Heaven was itself the oldest known alter? This is certainly not as clear as (B), which makes it crystal clear that it's The Altar of Heaven that's the earliest known altar, so we can ditch (C).


Notice that the portion in red is a modifier describing The Altar of Heaven. If we strip it out, we're left with "The Altar of Heaven and is the only altar..." This is incoherent - we need an initial verb to be parallel to "is." We can write "The Altar of Heaven IS x and IS y," but we certainly can't write "The Alter of Heaven and IS y." (D) is out.


Now the sentence begins with a modifier describing the Altar of Heaven, which appears to be the subject. Then we get a long "which" modifier, also describing the Altar of Heaven. But we never get a verb for our subject. So now we have a sentence fragment.

(E) is out, and (B) is our winner.