如果等差数列 $\left\{a_{n}\right\}$ 中, $a_{3}+a_{4}+a_{5}=12$, 那么 $a_{1}+a_{2}+\ldots+a_{7}=$ ($\qquad$)
Gaokao · Math · previous-year question
- A.14
- B.21
- C.28
- D.35
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