The 'd is a short form of "would" or "had".

Yes, it's either "would" or "had". You'll know which one it is based on the following verb. "Would" is always followed by the verb in the base form, and "had" (ie. past perfect "had") is always followed by the past participle. You'd ask = you would ask You'd asked = you had asked

would or had

you would,they would,he would. or you had , they had,he had depends on the sentence http://www.thefreedictionary.com/he%27d

Is the contraction of: You would....They would....he would