Looking on the internet deeply has found these results:

I concern is the most popular phrase on the web.

I have concerned 11,170 results on the web	I concern 114,700 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
v. con·cerned, con·cern·ing, con·cerns. v.tr. 1. To have to do with or relate to: an article that concerns the plight of homeless people. 2. To be of interest or ... Present I concern you concern he concerns we concern you concern they concern. Perfect I have concerned you have concerned he has concerned we have ... Present perfect. I have concerned you have concerned he/she/it has concerned we have concerned you have concerned they have concerned ... you were concerning they were concerning. Present perfect. I have concerned you have concerned he has concerned we have concerned you have concerned	Present I concern you concern he concerns we concern you concern they concern. Perfect I have concerned you have concerned he has concerned we have ... I concern about my grade very much. (Incorrect!) I am (very) concerned about my grade. (Correct). Explanation: The word concern can be either a verb or a noun. Colombia. Spanish. Hola me podrian ayudar con un par de ejemplos en ingles con la expresion "As far as I concern". Gracias ;). Nicolas Bustillo, Jan 3, 2011. v. con·cerned, con·cern·ing, con·cerns. v.tr. 1. To have to do with or relate to: an article that concerns the plight of homeless people. 2. To be of interest or ...

I have concerned

11,170 results on the web

I concern

114,700 results on the web

More popular!

v. con·cerned, con·cern·ing, con·cerns. v.tr. 1. To have to do with or relate to: an article that concerns the plight of homeless people. 2. To be of interest or ...
Present I concern you concern he concerns we concern you concern they concern. Perfect I have concerned you have concerned he has concerned we have ...
Present perfect. I have concerned you have concerned he/she/it has concerned we have concerned you have concerned they have concerned ...
you were concerning they were concerning. Present perfect. I have concerned you have concerned he has concerned we have concerned you have concerned

Present I concern you concern he concerns we concern you concern they concern. Perfect I have concerned you have concerned he has concerned we have ...
I concern about my grade very much. (Incorrect!) I am (very) concerned about my grade. (Correct). Explanation: The word concern can be either a verb or a noun.
Colombia. Spanish. Hola me podrian ayudar con un par de ejemplos en ingles con la expresion "As far as I concern". Gracias ;). Nicolas Bustillo, Jan 3, 2011.
v. con·cerned, con·cern·ing, con·cerns. v.tr. 1. To have to do with or relate to: an article that concerns the plight of homeless people. 2. To be of interest or ...