A non-trivial absolute value on an algebraic number field $K$ restricts to $Q$ non-trivially. Let $|\cdot|$ be a non-trivial absolute value over an algebraic number field over $K$. Then restriction of $|\cdot|$ to $Q$ is non-trivial.(i.e. $i:Z\to K$ embedding allows $Q\to K$ embedding. $|\cdot|$ is restricted to the image of $Q\to K$ embedding.)
$\textbf{Q:}$ Since non-trivial absolute values over $Q$ are either equivalent to the absolute value defined by $p-$valuation($p$ is a prime in $Z$) or equivalent absolute value in $R$, can I say this restricted absolute value must be the absolute value coming from $R$(real number)?(In particular, do I know this absolute value ultrametric or not?) I do not see any reason this has to be the case.  
This is related to Taylor-Frohlich Pg 70. (2.21) statement.
 A: Here is a counterexample where an absolute value on $K$ restricts to a nonarchimedean absolute.  Up to equivalence of absolute value, it is the only counterexample.
Let $p$ be a prime number, and let $\mathfrak p$ be a prime of $A = \mathcal O_K$ lying over $p\mathbb Z$.  Since $A$ is a Dedekind domain, the localization $A_{\mathfrak p}$ is a discrete valuation ring with unique maximal ideal $\mathfrak p A_{\mathfrak p}$.  Let $\varpi$ be a generator of the unique maximal ideal of $A_{\mathfrak p}$.  Then
$$pA_{\mathfrak p} = \mathfrak p^e A_{\mathfrak p} = \varpi^e A_{\mathfrak p}$$
where $e \geq 1$ is the ramification index of $\mathfrak p$ over $p$.  Every nonzero element of $K$ can be written uniquely as $u \omega^n$, for $u \in A_{\mathfrak p}^{\ast}$ and $n \in \mathbb{Z}$.  Define an absolute value on $K$ by
$$|u \omega^n| = \rho^{n}$$
where $\rho = p^{\frac{-1}{e}} \in (0,1)$.  This absolute value is nonarchimedean, since it is coming from a DVR.  We can write $p = \varpi^e u_1$, for $u_1 \in A_{\mathfrak p}^{\ast}$.  
If we restrict $| \cdot |$ to $\mathbb{Q}$, we get the $p$-adic absolute value: every nonzero rational number can be uniquely written as $ap^n$, for $a$ a rational number relatively prime to $p$.  Then
$$|ap^n| = |a \varpi^{en} u_1^n| = \rho^{en} = p^{-n}$$
which is the $p$-adic absolute value.  
Using Ostrowski's theorem, the absolute values on $K$ can be completely classified by how they restrict to $\mathbb Q$; if the restriction is archimedean, the absolute value comes from an embedding of $K$ into $\mathbb C$.  If it is archimedean, the absolute value comes from a unique prime $\mathfrak p$ of $\mathcal O_K$ as above.  
