频率合成器可分为直接式频率合成器、锁相频率合成器和()
参考答案:
阅读短文,判断正(T)误(F)。
Hello, I am Mary. My father is Mr. Smith. He is a businessman. My mother is Mrs. Smith. She is a doctor.
I have two brothers, John and Tom. John is twenty-four years old. He is a bus driver. Tom is eleven. I am
thirteen years old. We are students. We love my family.
( ) 1. My name is Mary Smith.
( ) 2. My family has four people.
( ) 3. My father is a doctor.
( ) 4. Tom is a student.
( ) 5. John is older than Tom.
爱琴文明是古希腊文明的渊源,它的中心最早在( )
A.克里特岛
B.阿提卡半岛
C.迈锡尼城
D.萨拉米斯岛