How many back vowels are there in English? What are they?6, and they are /u:/, /u/, /ɔ:/, /ɔ/, /ɑ:/ and /ʌ/.
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How can we subdivide the six back vowels?They can be subdivided into those that are high (/u:/ and /ʊ/), mid (/ɔ:/ and /ʌ/), and low (/ɑ:/ and /ɒ/)
A. 对
B. 错
实验中编码器供电电压是多少?( )
A. 3.3V
B. 10V
C. 5V
D. 6V
下列哪个通道引脚可以接编码器信号线()
A. TIM1_CH1
B. TIM2_CH3
C. TIM4_CH3
D. TIM6_CH1
实验中设置编码器的工作模式为( )
A. 仅在TI1计数
B. 仅在TI2计数
C. 在TI1和TI2计数
D. 不计数