1. They help make your new knowledge stay longer. - In this sentence, "help" is the main verb, and "make" is a verb in a reduced form as a part of the phrase "help make." The phrase "make your new knowledge stay longer" functions as the object of the verb "help."2. The verb "make" is the main verb in the phrase "make your new knowledge stay longer," where "make" is followed by its object "your new knowledge" and its complement "stay longer."3. The use of "help" with a verb in its reduced form (without "to") is grammatically correct and commonly used. This structure is known as a helping verb or auxiliary verb, which is used to help express the tense or aspect of the main verb.4. The sentence demonstrates two uses of the verb "help": as a helping verb before an infinitive (without "to") and as an independent verb with its own object and complement.5. The infinitive form "to make" is not explicitly present after "help" in this sentence, which is a common stylistic choice. However, it is grammatically correct to include "to" if desired: "They help you to make your new knowledge stay longer."