Even the newest gardener realizes that plants die without water; what is not so well known is that plants die equally decisively, though not so quickly, if they are over watered. Beginners usually decide to play it safe and keep their potted plants thoroughly wet. In consequence, death by drowning is one of the commonest disasters to befall the plants of a new horticulturist. Plants wither away if they don"t get enough water, and this draws attention to their problem. A plant that has been slightly under watered so that it droops strikes terror into the heart of its new owner. But it will, in fact, recover completely as long as rescue comes in time and the process is not repeated too often. Over watered plants, unfortunately, do not give any such obvious signal; slowly they cease to thrive and the first visible indication of serious trouble is a yellowing of the lower leaves. Unless the over watered pot soil is given a considerable period without water, during which time the plant will continue to look wretched, it will suddenly collapse in exactly the same way as the under watered plant --- but with no chance of being revived because the roots have rotted away.
5. Judging from the text, a horticulturist is one who ____.
A. raises animals
B. grows plants
C. gives advice to new gardeners
D. studies the watering of plants
6. One of the commonest disasters that happen to plants of a new gardener is ____.
A. underwatering
B. overwatering
C. lack of fertilizer
D. a withering disease
7. Which of the following plants has more chance of complete recovery? ____
A. A plant with its leaves drooping.
B. A plant with its lower leaves yellowing.
C. A plant with its roots rotting away.
D. A plant that slowly cease to thrive.
8. The purpose of the writer in writing this passage is ____.
A. to give general instructions for gardening
B. to give practical instructions for growing potted plants
C. to draw attention to the problem of underwatered plants
D. to draw attention to the problem of overwatered plants