已知关于x的方程$x^2-\left(2k+1\right)x+4\left(k-\frac{1}{2}\right)=0$
（1）求证：不论k取什么实数值，这个方程总有实数根；
（2）若等腰三角形ABC的一边长a=4，另两边的长b，c恰好是这个方程的两根，求△ABC的周长。

图P点位置，同时符合①东半球；②北半球；③热带三个条件的是（    ）

写出下面单词的意思。

    Alice is a white dog. She is two. Bob is a brown dog. Bob and Alice are good friends. Look at the two dogs.

Bob: Good morning!

Alice: Good morning!

Bob: What's this?

Alice: It's a jacket. It's my sister's. Oh, my sister is Grace.

Bob: What's that?

Alice: It's a book. It's Miss Miller's book. She is an English teacher.

Bob: Well, dogs don't like books.