他买下了那幢他认为一两年后会升值的房子。（which）
热心网友
He bought the house which he thoufht would appreciate in a year or two.
热心网友
他买下了那幢他认为一两年后会升值的房子。He bought the house which he believed appreciation in value.
热心网友
He bought the house which he thought it will be upward revaluation in one or two years.