题目6A. <img src="https://tihai-oss-cloud.itihey.com/img/2201e0af8b70c62b6cc86d2d8afcc7a9.png">B. <img src="https://tihai-oss-cloud.itihey.com/img/b151e3c11250a321ef720f9d70477089.png">C. <img src="https://tihai-oss-cloud.itihey.com/img/3d7462aecd28ce6be688382944ea90d2.png">D. <img src="https://tihai-oss-cloud.itihey.com/img/b4b87131a1d69ec27223dc9e075d2216.png">