(4) since +時間起點
(5) for + 一段時間
(1) to change
(2) to become
(3) to turn (to be) + adj
(4) to get + adj
(5) to improve
(6) to deteriorate English verbs have a form called “perfect form” (完成式), which is made up of the auxiliary verb have plus the past participle of the verb.
[例] 動詞change的完成式型態有 have changed, has changed, had changed, has been changed等等
These perfect forms are quite often used in English, but Chinese verbs do not have this form. As a result, Chinese students often make the mistake of not using the perfect form in an English sentence where the perfect form should have been used. They often used the past (過去簡單式) or the present tense forms (現在式), instead of the perfect form.
When one speaks about a point of time (某一個時候), like "last night," one must use the past tense form (過去式),
Last night the weather suddenly changed.
But when one speaks about a period of time (某一段時間), like "in the last few weeks," one must use the perfect form (完成式).
In the last few weeks the weather has changed a lot.
It can help you make sure you use the perfect form always correctly if you note that whenever in the sentence there is the adverb recently, always, since or a prepositional phrase with for . . . or in . . . , like for three months or for a long time or in the last 10 years, then almost always the verb should be in the perfect form. Here are examples of student sentences, with corrections:
Recently I'm very busy. (X)
Recently I've been very busy.
Drug use is always a big problem in this country. (X)
Drug use has always been a big problem in this country.
I'm interested in psychology for a long time. (X)
I've been interested in psychology for a long time.
I play the piano for years. (X)
I've played the piano for years.
It is ten years since we moved to Taipei. (X)
It has been ten years since we moved to Taipei
Some verbs in English which themselves express change, like to change, to become, to turn (to be) + adjective, to get + adjective, to improve, to deteriorate, etc. are very rarely used in the present tense form. Most of the time they are in the perfect or the past tense form.
Just remember: whenever you have in mind the Chinese verb 變(成)了, use the perfect form. Examples:
Taipei becomes a very prosperous, international city. (X)
Taipei has become a very prosperous, international city.
Our society changes very fast. (X)
Our society has changed very fast.
Law and order deteriorates in Taiwan. (X)
Law and order has deteriorated in Taiwan.