因为……，所以……

English hates "Because it rained, therefore I stayed home" because it feels doubled up. Chinese does the opposite: 因为…所以… is the normal, complete pair and nobody hears it as repetitive. In fast WeChat talk, people often drop 因为 and keep 所以: 下雨了，所以我没去。 Keeping 因为 and dropping 所以 is also possible, but in careful speech or writing it can leave the sentence hanging like an unfinished thought. If someone simply asks you why, give the reason alone: 因为下雨。 No 所以 belongs there. “因为我不喜欢运动，所以这两个我都不喜欢。” ── [《你喜欢看老电影吗？》](/read/do-you-like-old-movies#s9)

所以 is the first word of the result half, which means it comes before whoever does the action. 因为下雨，所以我没去 is right. 因为下雨，我所以没去 sounds broken to native ears. Compare 就, which is a little word glued right next to the verb: 因为下雨，我就没去。 Picture 所以 as the hinge at the seam of two doors, and 就 as a sticker on one door.

所以 joins the two halves of a sentence; 就 is a small word that sits just before a verb and adds a "then, as a result" flavor. You can use both together: 因为下雨，所以我就没去。 You can also skip 所以 in chat and keep 就: 因为下雨，我就没去。 But 就 can never sit in the linker spot, so 因为下雨，就我没去 falls apart. The same trap shows up when learners answer a question with 就 instead of 因为.