since moving to a foreign-affiliated company, I've come to realise (think/believe) that Japan is lagging behind
Since starting work at a foreign company, I've come to realise (think/believe) that Japan is behind the times
After transferring to a foreign company, I've come to realise that Japan is lagging behind
「外資」＝ a foreign (company) / a foreign-affiliated (company)
「転職」＝ move jobs / change jobs / transfer
「日本は遅れてる」＝ Japan is behind (the times) / Japan is lagging behind
「思うようになった」＝ I've come to think / I've come to realise / I've come to believe
「外資に転職してから日本は遅れてるって思うようになった」＝ since moving to a foreign-affiliated company, I've come to realise (think/believe) that Japan is lagging behind / Since starting work at a foreign company, I've come to realise (think/believe) that Japan is behind the times / After transferring to a foreign company, I've come to realise that Japan is lagging behind
「～をしてから」＝ since ～ing / since I 動詞の過去形 / after ～ing
「～するようになった」＝ come to 動詞の原形 / started ～ing
※現在完了形を使う場合が多い！
「大学に入学してから、夜更かしするようになった」＝ since starting at university, I've come to stay up too late (at night) / after entering university, I started staying up too late (at night)
「仕事をやめてから、ジムに通うようになった」＝ since quitting my job, I've started going to the gym (more)
「彼氏ができてから、料理を作るようになった」＝ after getting a boyfriend, I came to do more cooking
イギリス 
