TOEFL Reading: ETS-TOEFL阅读机经 - NY3PNI1P8D4LEP2ML$

The author mentions "tomatoes, corn, snapdragons and roses" in order to A. Name some of the most well-developed and commonly grown domestic plants B. Provide examples of plants whose flowering is not determined by length of day C. Demonstrate that the neutral plants are more common than long-day or short-day plants D. Support the claim that some plants flower at night as well as during the day