3.In each of the following groups of words, there are four underlined letters or letter combinations marked A, B, C and D. Compare the underlined parts and identify the one that is different from the others in pronunciation.
A、useless
B、endless
C、unless
D、hopeless
Why is compared to a fertilizer in Para. 3?
A、They both absorb light.
B、They both store heat.
C、They both help plants grow.
D、They both cause global warming
Pets____constant care are not suitable for people with little spare time.