In Microsoft Word, you can use a shortcut to select one sentence at a time. Press and hold down the Ctrl key and while continuing to hold down this key click with your left mouse button anywhere within the sentence you want to select or highlight.
Once a sentence has been selected let go of the Ctrl key, and you can press the Del key to delete that sentence or right-click and it to change its properties.
Bonus Tip: If you continue to hold down the Ctrl key after a sentence has been selected and click and drag that sentence you can make a copy of that sentence where you let go of the button.