20．It was four o'clock in the afternoon_____he and his grandpa reached the museum in Guanghan, _____an official warmly received them.

       A．that; where             B．when; that               C．when; where           D．that; when

It was four o’clock in the afternoon_______ he and his grandpa reached the museum in Guanghan,________ an official warmly received them.

A that, where        B when, where    C where, when   D that, which25

20．It was four o'clock in the afternoon_____he and his grandpa reached the museum in Guanghan, _____an official warmly received them.

It was at four o'clock in the afternoon ____ he and his grandpa reached the museum in Guanghan.

It was at four o'clock in the afternoon ____ he and his grandpa reached the museum in Guanghan.

1. A.
   while
2. B.
   that
3. C.
   when
4. D.
   as