21£®X-rays were first discovered by _______ German scientist, Wilhelm K£®Rontgen, in 1895, almost by ________ accident.

       A£® the, /               B£®a, an                 C£®a, /                     D£®the, the

22£®— Why don’t you take a taxi there? It’ll save you a lot of time.

    — _________.

   A£®Thank you anyway!                        B£®Yes, let’s£®

       C£®Good idea!                                      D£®That’s all right.

23£®Most experts predict that all these changes will lead to a strong and powerful China, ________ that can surprise the whole world£®¡¡

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