It should be of no surprise that your opponent will attempt to block your pass by trying to create space between the two of you. Often as you attempt to pass they'll utilize their free leg to push against your face to do so. Sometimes if the leg goes past the face it will continue to your armpit where, again, leverage can be created. This can be especially annoying when you have no answers, but luckily there is one! While your opponent focuses their energy on defense, hook their pinned leg from the outside with your leg. Then triangle your legs together. Scoot your body down until your hips are against your opponents knee and hip in to finish the Knee Bar. While you finish, be aware of your base and try not to get swept in the process. If your opponent turns hard to free their knee you can simple pass as they no longer have any viable hooks.