is

动词 be:

1. have the quality of being; (copula, used with an adjective or a predicate noun)
   同义词：be
2. be identical to; be someone or something
   同义词：be
3. occupy a certain position or area; be somewhere
   同义词：be
4. have an existence, be extant
   同义词：exist, be
5. happen, occur, take place
   同义词：be
6. be identical or equivalent to
   同义词：equal, be
7. form or compose
   同义词：constitute, represent, make up, comprise, be
8. work in a specific place, with a specific subject, or in a specific function
   同义词：be, follow
9. represent, as of a character on stage
   同义词：embody, be, personify
10. spend or use time
    同义词：be
11. have life, be alive
    同义词：be, live
12. to remain unmolested, undisturbed, or uninterrupted -- used only in infinitive form
    同义词：be
13. be priced at
    同义词：cost, be

1. Spain is our favorite holiday spot.
   西班牙是我们喜欢的度假地点。
2. The boy is 150 centimeters tall.
   这个男孩有150厘米高。
3. There is no doubt about it.
   那是毫无疑问的。
4. The room is 15 feet in length and 10 feet in breadth.
   这房间长15英尺，宽10英尺。
5. That's the way it is.
   就是这么回事。
6. The video is programmed to switch on at ten o'clock.
   电视机设定在10点钟自动打开。
7. A friend in need is a friend indeed.
   患难之交才是真朋友。
8. Pain past is pleasure.
   过去的痛苦即是快乐。

is

v.（动词）
Third person singular present indicative of be
be的第三人称单数现在陈述语气词

来源：
Middle English
中古英语
from Old English * see es-
源自 古英语 *参见 es-