（ ）I don’t know __________.

A．how often he visits his grandparents

B．how soon will he come back

C．how many students are there in his class

D．how long is the bridge

[单选题]I don't know ________.A.who were theyB.who they areC.who are theyD.who they

[单选题]I don’t know ______ to deal with such matter.A.whatB.howC.whichD./

[单选题]I don't know ______ standing beside the headmaster.A． the girl's nameB． the name of the girl'sC． the name of the girlD． the name's of the girl

[单选题]I don't know his address, ______.A．otherwise I will write to himB．otherwise I would write to himC．otherwise I had written to himD．otherwise I would have written to him

[主观题]H．is (one) name is Mike. But I don’t know his family name.

[单选题]I don't know ________ to deal with such matter.A.what B. how C. which D. /

[单选题]I don't know _________ to deal with such matter.A.what B.how C.which D./

[单选题]I don't know ________ to deal with such matter.A.whatB.howC.whichD./

[单选题]I don't know the [origin]of this custom.A.natureB.reasonC.beginningD.result

[单选题]I don't know the [origin]of this custom.A.natureB.reasonC.beginningD.result