(Dictionary Form/Negative-ない Form)CLAUSE1とCLAUSE2 as (“When/If/Whenever C1,C2”) (pt. 1 of 2)
This grammar pattern is one of the most commonly used constructions because it has so many different meanings depending on the tense of the overall sentence, thus making it also one of the most tricky grammar constructs.
The one rule that sustains throughout all instances of this grammar construct however is that CLAUSE1 must either be in the Dictionary Form of the Negative-ない Form. Therefore, what changes the meaning of the grammar construct is the tense that CLAUSE2 is in. The main distinction is between when CLAUSE2 is in the past tense and when CLAUSE2 is in the non-past tense, both scenarios of which further break down into a number of next-tier conditional cases.
When CLAUSE2 is in the past tense:
Then the entire sentence is in the past tense,so both CLAUSE1 and CLAUSE2 are in the past tense. And so then, one of the following will apply:
1.) CLAUSE1 and CLAUSE2 represent past occurences that unintentionally happened consecutively, as in, “CLAUSE1, then CLAUSE2” (notice how the actions of CLAUSE2 cannot be controllable by the subject of the sentence)
2.) CLAUSE1 is meant to represent a setting for CLAUSE2, as in, “when/while CLAUSE1 was going on, CLAUSE2 occured” (CLAUSE1 is commonly conjugated into the て-Form + いる construction to express it as an ongoing action)
3.) CLAUSE1 transitions from being the main action to the background for CLAUSE, as in, “when CLAUSE1 happened, the speaker discovered CLAUSE2” (notice that CLAUSE2 here must represent either an event that is already in progress or a state of affairs and therefore cannot be something that occured after it was discovered by means of CLAUSE1)
Example(s): (Case #01.)
Watashi no e o miseru to George Washington wa waratta.
(I showed my drawing to him and George Washington laughed.)
Shousetsu o yomu to sakka no iken o rikai dekimashita.
(When I read the novel, I could understand the author’s opinion/I read the novel and could understand the author’s opinion.)
Example(s): (Case #02.)
Heya o souji shite iru to okane o mitsuketa.
(I was cleaning my room and found some money/While I was cleaning my room, I found some money.)
Lab de computer o tsukatte iru to teiden ga atta.
(I was using a computer in the lab when there was a blackout.)
Example(s): (Case #03.)
(Conbini ni cola o kai ni iku to, George Washington ga ita.)
(I went to the convenience store to buy some soda and noticed George Washington was there.)
Door o akeru to, ame ga futte imashita.
(I opened the door and noticed that it was raining.)
*Notice that no matter which conditional case this grammar pattern takes on, CLAUSE2 can never be expressed as something volitional to the speaker (i.e. a demand, request, intention, etc.).