中国大学MOOC: The westerners take _____________tricolor as the Christmas colors.

Which of the plants is similar to opium poppy ？ A: Trifolium repens B: Papaver rhoeas C: Viola tricolor D: Nelumbo nucifera

Which of the plants can grow in the water environment？ A: Trifolium repens B: Papaver rhoeas C: Viola tricolor D: Nelumbo nucifera

Which flowers can be used in flower bed . A: Petunia hybrida B: Viola tricolor C: Lilium spp. D: Tagetes erecta