I'm often encountering the phrase have become. I just wonder if the proper word there is became not become, am I right or I've just missed out a rule? Can anyone explain it for me.
The verb form is called present perfect, and it consists of the word have or has followed by the past participle of the verb. Often, the past participle is identical to the past tense of the verb, but in the case of the verb to become (verbs are generally named collectively by the infinitive), the past participle is identical to the present tense. Therefore has become or have become is correct, depending on person and number: I have become You have become He/She/It has become We have become They have become
You use became when the action is finished, particularly if you give a past time, like: He became president in 1996/when he was a very young man. When you talk about something that happened in the past, but you don't give a past time (e.g. 1996, when he was a very young man), and particularly if you want to indicate that the action still affects the present, or has only just happened, you use present perfect tense with the past participle--become--as Cogito describes: He has become president. When you listen to news broadcasts, you hear the newsreader often starts with present perfect, then continues with past simple: Catherine Middleton has become HRH The Duchess of Cambridge. She became a member of the British royal family when she married Prince William. or: A NATO airstrike has killed Col Gadaffi's son. It killed him on Saturday evening when an attack was launched at the house he was staying in.
