引起铸件热裂的原因较多,指出下列项次中,会引起热裂的条目()
A.线收缩受阻
B.厚薄悬殊
C.落砂过早
D.硫磷偏低
参考答案:A, B, C
Dear me! Just _________ at the time! I _________ no idea it was so late.
A.look, have
B.looking, had
C.look, had
D.looking, have
“三无”是指无______、无______、无______。