(1)He/she/it will be responsible for… [future tense of “be” for第三人稱單數]
he/she/it is responsible for……. [present tense of “be” for第三人稱單數]
He/she/it was responsible for…… [past tense of “be” for第三人稱單數]
(2)they/we/I will be responsible for… [future tense of “be” for除第三人稱單數之外]
they/we are responsible for…. [present tense of “be” for除第三人稱單數之外]
I am responsible for…………. [present tense of “be” for除第三人稱單數之外]
they/we were responsible for…… [past tense of “be” for除第三人稱單數之外]
I was responsible for…………… [past tense of “be” for除第三人稱單數之外]