Had been investigating.
The present perfect progressive tense of "investigate" is "has been investigating."
The past progressive tense of the word "plan" is "was planning".
The present perfect tense of "hid" is "have/has hidden."
The present perfect tense of "exist" is "has/have existed."
The present perfect tense of "was" is "have been".
The present perfect tense of "clap" is "have clapped" or "has clapped."
The past progressive tense of the word "plan" is "was planning".
Have/Has been investigating.
The present perfect progressive tense of the verb "to investigate" is "have been investigating."
The past perfect progressive tense of "to investigate" is "had been investigating."
The present progressive tense of investigate is:I am investigating.You/We/They are investigating.He/She/It is investigating.
There are two forms of the present perfect tense: simple present perfect (I have eaten) and progressive present perfect (I have been eating). Both forms use "have" or "has" with the past participle of the main verb to indicate an action that started in the past and has relevance to the present.
Present perfect tense.
The present perfect tense of "hid" is "have/has hidden."
Actually, "have" is the present tense form for first and second person plural (I, you, we, they) while "has" is the present tense form for third person singular (he, she, it). For example: "I have, you have, we have, they have" versus "he has, she has, it has."
present tense past tense future tense present perfect tense past perfect tense future perfect tense present progressive tense past progressive tense future progressive tense present perfect progressive tense past perfect progressive tense future perfect progressive tense
The present perfect tense of "are" is "have been."
The six tenses in English are present, past, future, present perfect, past perfect, and future perfect. Each tense indicates when an action or state of being occurred in relation to the present moment.