46. They couldn't go out because of the heavy rain

- because of N/Ving : bởi vì

47. Although he was ill, he took part in the contest anyway

- although S V; mặc dù

48. He started studying in Stanford University 3 years ago

- start Ving

49. Unless I had known the answer, I wouldn't have told you

- unless = if..not

50. Would you mind showing me the way to the museum?

- Would you mind Ving?

$46.$ They couldn't go out because of the heavy rain

`⇒` Because of + N / V-ing $:$ Bởi vì

$47.$ Although he was ill, he took part in the contest anyway

`⇒` Although $:$ Mặc dù

$-$ Although + S + V + O 

$48.$ He started studying in Stanford University 3 years ago

`⇒` Start + V-ing $:$ Bắt đầu làm gì đó

$49.$ Unless I had known the answer, I wouldn't have told you

`⇒` Unless $=$ If ... not

$50.$ Would you mind showing me the way to the museum?

`⇒` Would you mind + V-ing ? $:$ Bạn có thích làm gì đó không