Because my smartphone isn’t working well, I will take it back to the shop.
Giải thích
=> My smartphone isn’t working well, so I will take it back to the shop.
Or: My smartphone isn’t working well; therefore, I will take it back to the shop.
=> My smartphone isn’t working well, so I will take it back to the shop.
Or: My smartphone isn’t working well; therefore, I will take it back to the shop.