设某路模拟信号的频率为0～4kHz，信号的取值为－1.20～1.20V，若按PCM方式进行基带传输，均匀量化。设某路模拟信号的频率为0～4kHz，信号的取值为-1.20～1.20V，若按PCM方式进行基带传输，均匀量化

力原文： Chin’s US $ 56.56 billion of importsnd US $ 60.51 billion of exports of hi-tech products for the first 4 months of the yer represent the country’s 7-month long trde surplus on hi-tech products since lst October. The hi-tech foreign trde from Jnury topril posted yer-on-yer rise of 26.8 percent. The hi-tech exports went up fster thn the imports by 12 percent. The hi-tech trde surplus totled more thn US $ 3.9 billion for the first 4 months. The hi-tech exportsccounted for 27.8 percent of the totl exports for the first 4 months. USS 35.38 billion, or 58.5 percent of hi-tech exports, cme from integrted circuit, color TV, mobile phones,ndutomtic dt processing equipment. They hve won lrger orderst higher prices. Chin’s hi-tech trde surplus hs lsted for______ so fr.4 months B．7 months C．4 yers D．7 yersA．4 monthsB．7 monthsC．4 yearsD．7 years