18 It is acknowledged that 19 It is well-known that 20 It is estimated that
It is + 标志词(形容词或动词的过去分词)+that+(should)+do 标志词:appropriate、desirable、essential、important、impossible、necessary、natural、normal、urgent、vital 解题步骤: 1、找到标志词 2、选出动词do 学位英语真题汇编 1、It is necessary that we ___...
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