雨が降りだしたとき何をしていましたか。

rain

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

to descend; to go down; to come down; to be handed down (of an order, judgment, etc.); to pass (of time); to surrender; to capitulate; (often in neg. form) to be less than; to be inferior to; to have the runs; to have diarrhea

regular (stops at every station) Jouetsu-line Shinkansen

what; how many; you-know-what; that; whatsit; what's the expression; what do you call them; what?; hey!

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to do; to cause to become; to make (into); to turn (into); to serve as; to act as; to work as; to wear (clothes, a facial expression, etc.); to judge as being; to view as being; to think of as; to treat as; to use as; to decide on; to choose; to be sensed (of a smell, noise, etc.); to be (in a state, condition, etc.); to be worth; to cost; to pass (of time); to elapse; verbalizing suffix (applies to nouns noted in this dictionary with the part of speech "vs"); creates a humble verb (after a noun prefixed with "o" or "go"); to be just about to; to be just starting to; to try to; to attempt to

indicates a question (sometimes rhetorical); or; whether or not; some- (e.g. something, someone); indicates doubt, uncertainty, etc.; emphatic prefix; suffix forming adjectives or adverbs; in that way