Usually, one-sentence paragraphs are empty statements and they must be edited out. The true introduction is likely to be found in your next paragraph. Remove these one-liners entirely, connect them to the next paragraph, or develop them into substantive introductions. The Empty Introduction Essays sometimes begin with several sentences that wander around without really saying anything. These sentences are often simply variations of the title of the paper.
Skiing is very exciting sport.
There are many people who take it up for the excitement. The rewards of skiing can be great. There is nothing like the excitement of skiing down a snowy hill. The writer is hitting the reader over the head with that idea. The writer is skiing around trying to find a subject or an entrance into a subject.